diff --git a/src/redturtle/prenotazioni/content/prenotazione_type.py b/src/redturtle/prenotazioni/content/prenotazione_type.py
index 52ccb122..393fa36c 100644
--- a/src/redturtle/prenotazioni/content/prenotazione_type.py
+++ b/src/redturtle/prenotazioni/content/prenotazione_type.py
@@ -28,11 +28,6 @@ class IBookingAdditionalFieldsSchema(model.Schema):
         required=True,
         default="",
     )
-    description = schema.TextLine(
-        title=_("booking_additional_field_description", default="Descrizione"),
-        required=False,
-        default="",
-    )
     type = schema.Choice(
         title=_("booking_additional_field_type", default="Tipo"),
         required=True,
@@ -43,6 +38,11 @@ class IBookingAdditionalFieldsSchema(model.Schema):
         required=False,
         default=False,
     )
+    description = schema.TextLine(
+        title=_("booking_additional_field_description", default="Descrizione"),
+        required=False,
+        default="",
+    )
 
 
 class IPrenotazioneType(model.Schema):
@@ -104,6 +104,14 @@ class IPrenotazioneType(model.Schema):
         },
     )
 
+    model.fieldset(
+        "additional_fields",
+        label=_("booking_additional_fields_schema_title"),
+        fields=[
+            "booking_additional_fields_schema",
+        ],
+    )
+
 
 @implementer(IPrenotazioneType)
 class PrenotazioneType(Item):
diff --git a/src/redturtle/prenotazioni/restapi/services/booking/update.py b/src/redturtle/prenotazioni/restapi/services/booking/update.py
index 583877df..cd704297 100644
--- a/src/redturtle/prenotazioni/restapi/services/booking/update.py
+++ b/src/redturtle/prenotazioni/restapi/services/booking/update.py
@@ -41,48 +41,34 @@ def handle_additional_fields(self):
 
             booking_type = self.context.get_booking_type()
 
+            # validate additional fields
+            # TODO: refactor this code to a separate method to avoid code duplication
             for field_schema in booking_type.booking_additional_fields_schema or []:
-                field = list(
-                    filter(
-                        lambda i: i.get("name") == field_schema.get("name"),
-                        additional_fields,
-                    )
-                )
-
-                if not field and field_schema.get("required", False):
-                    raise BadRequest(
-                        api.portal.translate(
-                            _(
-                                "Additional field '${additional_field_name}' is missing.",
-                                mapping=dict(
-                                    additional_field_name=field_schema.get("name")
-                                ),
-                            )
-                        )
-                    )
-                elif not field:
-                    continue
-
-                field = field[0]
-
-                try:
-                    if not field.get("value"):
+                field = None
+                for additional_field in additional_fields:
+                    if additional_field.get("name") == field_schema.get("name"):
+                        field = additional_field
+                        break
+
+                if field_schema.get("required", False):
+                    if not field or not field.get("value"):
                         raise BadRequest(
                             api.portal.translate(
                                 _(
-                                    "Additional field '${additional_field_name}' value is missing.",
+                                    "Additional field '${additional_field_name}' is missing.",
                                     mapping=dict(
                                         additional_field_name=field_schema.get("name")
                                     ),
                                 )
                             )
                         )
+                elif not field:
+                    continue
 
-                    # Validation
+                try:
                     field_types_validators.get(field_schema.get("type"))(
                         field.get("value")
                     )
-
                 except ValidationError as e:
                     raise BadRequest(
                         api.portal.translate(
diff --git a/src/redturtle/prenotazioni/vocabularies/voc_booking_additional_fiels_types.py b/src/redturtle/prenotazioni/vocabularies/voc_booking_additional_fiels_types.py
index 138c9fe0..c7e501ca 100644
--- a/src/redturtle/prenotazioni/vocabularies/voc_booking_additional_fiels_types.py
+++ b/src/redturtle/prenotazioni/vocabularies/voc_booking_additional_fiels_types.py
@@ -1,5 +1,4 @@
 # -*- coding: utf-8 -*-
-from zope.i18n import translate
 from zope.interface import implementer
 from zope.schema import TextLine
 from zope.schema.interfaces import IVocabularyFactory
@@ -30,7 +29,7 @@ def __call__(self, context):
                 SimpleTermFieldType(
                     "text",
                     "text",
-                    translate(
+                    context.translate(
                         _(
                             "label_booking_additional_field_textline",
                             default="Text line",