Validation for Custom fields - MDG - BP data model (BP_SALES)

Hello All

Need guidance on the below issue we are facing -

1. Extended MDG data model ( Model - BP and entity - BP_SALES ) and there added a new custom

field 'Industry Code'. The domain of this field has a custom value table and created a search help

for this column of table.

2. Now after adding this filed in 'Sales area' UI of 'ERP customer' it is showing search help and

we can select data from there. But if user enters some wrong data ( not in custom table) and press enter then it is

not showing any error. But for existing standard fields like 'Account Assignment Group' it is

showing error as 'The Entered Value Is Not on the List of Valid Values'.

We want same feature for custom field also. Would like to know how to do that.

Kiran