First of all your subject is meaningless. That is grounds for the discussion being rejected. Please use a meaningful subject in future. But as Rob has already engaged, I'll let it pass this time.
Secondly you say:
Certain table fields that do not appear on any transaction screen and are neither are there any Bapi to update those fields
And then you say
For a bp with role UKM000, there is a screen at the last for credit standing. It has a text field which Bapi_bupa_credit_standing_get and set is not able to handle.
So first you say it's table fields that you can't see in transaction screens nor BAPI, now you say you there is a screen with a text field that you can see.
So which is it? You entire question is very vague and woolly. How about sharing some specifics?
