diff --git a/phpstan-baseline.neon b/phpstan-baseline.neon
index be38431a..a54fd6f5 100644
--- a/phpstan-baseline.neon
+++ b/phpstan-baseline.neon
@@ -615,11 +615,6 @@ parameters:
 			count: 1
 			path: src/lib/Output/Generator/InMemory/Xml.php
 
-		-
-			message: "#^Parameter \\#1 \\$data of method Ibexa\\\\Rest\\\\Output\\\\Generator\\\\InMemory\\\\Xml\\:\\:transformDataForEncoder\\(\\) expects array, array\\|ArrayObject\\<\\(int\\|string\\), mixed\\>\\|bool\\|float\\|int\\|string\\|null given\\.$#"
-			count: 1
-			path: src/lib/Output/Generator/InMemory/Xml.php
-
 		-
 			message: "#^Access to an undefined property Ibexa\\\\Rest\\\\Output\\\\Generator\\\\Json\\\\JsonObject\\:\\:\\$\\#text\\.$#"
 			count: 1
diff --git a/src/contracts/Output/Generator.php b/src/contracts/Output/Generator.php
index 9f923670..ccb5c049 100644
--- a/src/contracts/Output/Generator.php
+++ b/src/contracts/Output/Generator.php
@@ -431,11 +431,4 @@ public function getData(): object
      * @return array<mixed>
      */
     abstract public function getEncoderContext(array $data): array;
-
-    /**
-     * @param array<mixed> $data
-     *
-     * @return array<mixed>
-     */
-    abstract public function transformDataForEncoder(array $data): array;
 }
diff --git a/src/contracts/Output/VisitorAdapterNormalizer.php b/src/contracts/Output/VisitorAdapterNormalizer.php
index 3f4f0851..43e26ecb 100644
--- a/src/contracts/Output/VisitorAdapterNormalizer.php
+++ b/src/contracts/Output/VisitorAdapterNormalizer.php
@@ -22,6 +22,8 @@ final class VisitorAdapterNormalizer implements NormalizerInterface, NormalizerA
 
     public const string ENCODER_CONTEXT = 'ENCODER_CONTEXT';
 
+    public const string OUTER_ELEMENT = 'outer_element';
+
     public function __construct(
         private readonly ValueObjectVisitorResolverInterface $valueObjectVisitorResolver,
     ) {
@@ -104,11 +106,28 @@ private function visitValueObject(
 
         $data = $generator->getData();
 
-        $normalizedData = $this->normalizer->normalize($data, $format, $context + [
-            self::CALLED_CONTEXT => true,
-        ]);
-        $normalizedData = $generator->transformDataForEncoder($normalizedData);
+        $normalizedData = $this->normalizer->normalize(
+            $data,
+            $format,
+            $this->buildContext($context, $format),
+        );
 
         return $normalizedData + [self::ENCODER_CONTEXT => $generator->getEncoderContext(get_object_vars($data))];
     }
+
+    /**
+     * @param array<mixed> $context
+     *
+     * @return array<mixed>
+     */
+    private function buildContext(array $context, ?string $format): array
+    {
+        $context += [self::CALLED_CONTEXT => true];
+
+        if ($format === 'xml') {
+            $context += [self::OUTER_ELEMENT => true, 'as_collection' => true];
+        }
+
+        return $context;
+    }
 }
diff --git a/src/lib/Output/Generator/InMemory/Xml.php b/src/lib/Output/Generator/InMemory/Xml.php
index df4453a7..e39981e0 100644
--- a/src/lib/Output/Generator/InMemory/Xml.php
+++ b/src/lib/Output/Generator/InMemory/Xml.php
@@ -8,6 +8,7 @@
 
 namespace Ibexa\Rest\Output\Generator\InMemory;
 
+use Ibexa\Contracts\Rest\Output\VisitorAdapterNormalizer;
 use Ibexa\Rest\Output\Generator\Data;
 use Ibexa\Rest\Output\Generator\Data\ArrayList;
 use Ibexa\Rest\Output\Generator\Json;
@@ -91,6 +92,7 @@ public function endDocument(mixed $data): string
         $vars = get_object_vars($data);
         $encoderContext = $this->getEncoderContext($vars);
         $encoderContext['as_collection'] = true;
+        $encoderContext[VisitorAdapterNormalizer::OUTER_ELEMENT] = true;
 
         $normalizers = [
             new ArrayListNormalizer(),
@@ -101,10 +103,7 @@ public function endDocument(mixed $data): string
         $encoders = [new XmlEncoder()];
         $serializer = new Serializer($normalizers, $encoders);
 
-        $normalizedData = $serializer->normalize($data, 'xml');
-        $normalizedData = $this->transformDataForEncoder($normalizedData);
-
-        return $serializer->encode($normalizedData, 'xml', $encoderContext);
+        return $serializer->serialize($data, 'xml', $encoderContext);
     }
 
     public function getEncoderContext(array $data): array
@@ -113,18 +112,4 @@ public function getEncoderContext(array $data): array
             XmlEncoder::ROOT_NODE_NAME => array_key_first($data),
         ];
     }
-
-    public function transformDataForEncoder(array $data): array
-    {
-        $firstKey = array_key_first($data);
-
-        if ($firstKey === null) {
-            return $data;
-        }
-
-        $data['#'] = $data[$firstKey];
-        unset($data[$firstKey]);
-
-        return $data;
-    }
 }
diff --git a/src/lib/Output/Generator/Json.php b/src/lib/Output/Generator/Json.php
index 2b520cc9..87a6c8be 100644
--- a/src/lib/Output/Generator/Json.php
+++ b/src/lib/Output/Generator/Json.php
@@ -339,9 +339,4 @@ public function getEncoderContext(array $data): array
     {
         return [];
     }
-
-    public function transformDataForEncoder(array $data): array
-    {
-        return $data;
-    }
 }
diff --git a/src/lib/Output/Generator/Xml.php b/src/lib/Output/Generator/Xml.php
index 9c9a7a47..8851efa2 100644
--- a/src/lib/Output/Generator/Xml.php
+++ b/src/lib/Output/Generator/Xml.php
@@ -274,9 +274,4 @@ public function getEncoderContext(array $data): array
     {
         return [];
     }
-
-    public function transformDataForEncoder(array $data): array
-    {
-        return $data;
-    }
 }
diff --git a/src/lib/Output/Normalizer/JsonObjectNormalizer.php b/src/lib/Output/Normalizer/JsonObjectNormalizer.php
index aee19b4c..06dbafb4 100644
--- a/src/lib/Output/Normalizer/JsonObjectNormalizer.php
+++ b/src/lib/Output/Normalizer/JsonObjectNormalizer.php
@@ -7,6 +7,7 @@
 
 namespace Ibexa\Rest\Output\Normalizer;
 
+use Ibexa\Contracts\Rest\Output\VisitorAdapterNormalizer;
 use Ibexa\Rest\Output\Generator\Data\ArrayList;
 use Ibexa\Rest\Output\Generator\Json\JsonObject;
 use Symfony\Component\Serializer\Normalizer\NormalizerAwareInterface;
@@ -26,6 +27,9 @@ public function normalize($object, ?string $format = null, array $context = []):
     {
         $vars = get_object_vars($object);
 
+        $isOuterElement = $context[VisitorAdapterNormalizer::OUTER_ELEMENT] ?? false;
+        unset($context[VisitorAdapterNormalizer::OUTER_ELEMENT]);
+
         $data = [];
         foreach ($vars as $key => $value) {
             if ($value instanceof ArrayList) {
@@ -35,7 +39,8 @@ public function normalize($object, ?string $format = null, array $context = []):
                 }
                 $data[$name] = $this->normalizer->normalize($value, $format, $context);
             } else {
-                $data[$key] = $this->normalizer->normalize($value, $format, $context);
+                $modifiedKey = $isOuterElement && count($vars) === 1 ? '#' : $key;
+                $data[$modifiedKey] = $this->normalizer->normalize($value, $format, $context);
             }
         }