diff --git a/backend/api/v1/modules/a76/items/schemas.py b/backend/api/v1/modules/a76/items/schemas.py
index 2c94f679..cad3a134 100644
--- a/backend/api/v1/modules/a76/items/schemas.py
+++ b/backend/api/v1/modules/a76/items/schemas.py
@@ -258,7 +258,7 @@ class LineItemUpdate(LineItemBase):
     )
 
 
-class LineItemResponse(BaseModel):
+class LineItemResponse(LineItemBase):
     """Schema for single item response"""
 
     id: int
diff --git a/backend/api/v1/modules/a76/items/service.py b/backend/api/v1/modules/a76/items/service.py
index 1e1f884d..bf8321af 100644
--- a/backend/api/v1/modules/a76/items/service.py
+++ b/backend/api/v1/modules/a76/items/service.py
@@ -299,13 +299,6 @@ class ItemService:
         if item_data.fa_data and item_data.fa_data.subitem_number is None:
             errors.add_required_error(field=f"fa_data.subitem_number")
 
-        # Validar apóstrofes en número de parte
-        if item_data.part_number_id and "'" in str(item_data.part_number_id):
-            errors.add_error(
-                field=f"part_number",
-                message=f"Advertencia: El Número de Parte contiene apóstrofes y serán omitidos",
-                code="WARNING_APOSTROPHE",
-            )
 
         # Si hay errores, lanzar excepción ANTES de intentar crear
         errors.raise_if_errors("Error al crear el item")
@@ -396,16 +389,6 @@ class ItemService:
             db_item.line_number,
         )
 
-        # Validaciones adicionales específicas del negocio
-
-        # Validar apóstrofes en número de parte
-        if item_data.part_number_id and "'" in str(item_data.part_number_id):
-            errors.add_error(
-                field=f"part_number",
-                message=f"Advertencia: El Número de Parte contiene apóstrofes y serán omitidos",
-                solution=None,
-                code="WARNING_APOSTROPHE",
-            )
 
         # Validar tipo de partida
         if hasattr(item_data, "item_type") and item_data.item_type:
@@ -446,14 +429,6 @@ class ItemService:
                 exclude_unset=True,
             )
 
-            # Map schema field names to model field names
-            if "part_number_id" in item_dict:
-                item_dict["part_number"] = item_dict.pop("part_number_id")
-            if "component_part_number_id" in item_dict:
-                item_dict["component_part_number"] = item_dict.pop(
-                    "component_part_number_id"
-                )
-
             # Update item fields
             for key, value in item_dict.items():
                 setattr(db_item, key, value)
diff --git a/frontend/src/lib/components/dashboard/invoices/edit/items/fa/main-data.svelte b/frontend/src/lib/components/dashboard/invoices/edit/items/fa/main-data.svelte
index e34ca647..afc25180 100644
--- a/frontend/src/lib/components/dashboard/invoices/edit/items/fa/main-data.svelte
+++ b/frontend/src/lib/components/dashboard/invoices/edit/items/fa/main-data.svelte
@@ -9,7 +9,7 @@
 	import ClassDialog from './class-dialog.svelte';
 	import type { Item, LineQuantities, LineFinancials, LineCustoms } from '$lib/api/dashboard/a76/items';
 	import type { Invoice } from '$lib/api/dashboard/a76/invoices';
-	import { companyStore } from '$lib/stores/company.svelte';
+	import { companyStore } from '$lib/stores/company.svelte';	
 
     let {
         lineItem = $bindable(),
@@ -110,10 +110,10 @@
 				(lineItem as any).description.description_english = classItem.description_en;
 			}
 		}
-	}
+	};
 
 	function handleUnitSelect(unit: any) {
-		lineItem.unit_of_measure = unit.id;
+		lineItem.unit_of_measure = unit.id;				
 		// Store unit code for display
 		(lineItem as any).unit_code = unit.code;
 		(lineItem as any).unit_description = unit.description || unit.description_en;
diff --git a/frontend/src/lib/components/dashboard/invoices/edit/items/items-tab-form.svelte b/frontend/src/lib/components/dashboard/invoices/edit/items/items-tab-form.svelte
index 9b16498a..a8e24e06 100644
--- a/frontend/src/lib/components/dashboard/invoices/edit/items/items-tab-form.svelte
+++ b/frontend/src/lib/components/dashboard/invoices/edit/items/items-tab-form.svelte
@@ -501,19 +501,26 @@
 
 		isSavingPreset = true;
 		try {
-			// Each item in builderItems is already a LineItem (no nested lines)
-			const cleanedItems = builderItems.map((item: Item, idx: number) => {
+			// We group everything as items for the template
+			const lines = builderItems.map((item: Item, idx: number) => {
 				return {
 					...cleanLineData(item),
-					line_number: item.line_number || idx + 1,
+					line_number: item.line_number || idx + 1, // Ensure line_number is present
 					id: undefined // Ensure no IDs are saved in the preset
 				};
 			});
 
+			const payloadItems = [
+				{
+					reference_number: builderItems[0]?.reference_number || undefined,
+					lines: lines
+				}
+			] as any;
+
 			await itemPresetsApi.create(activeCompanyId, {
 				name: createPresetName.trim(),
 				description: createPresetDescription.trim() || undefined,
-				items: cleanedItems
+				items: payloadItems
 			});
 
 			createPresetName = '';