Changing label on PCUI field

Hi All.

I'm trying to change a label for a field in PCUI (CRM 5.0) Application CRMD_BUS2000112. The field (ORDERED_PROD) is in a field group SRC_GDT_ITEM and this field group is in the field group SRC_DISPLAY_GDT_ITEM. The label displayed must change depending of the Business Transaction type, my idea was encapsulate the field ORDERED_PROD in a new field group ZYYYY with a variant and then use customizing for changing the Text but when i'm generating layout for the field group SRC_DISPLAY_GDT_ITEM the following error is displayed "Field Group Could not be read completely". Did i miss something ? a better solution for this ?

Thanks and best regards.