Creating FA (997) at transaction level

How to create a 997 doc for EDI transactions. We can create FA for Interchange and group level with help of wm.edi.util:generateFA service but what about generate FA for transaction level.

EDIFunctionalACKGuide suggest that validate incoming EDI doc and then use error array return by validate service to map AK3 and AK4 segment in FA(997 doc). But I do not know the mean of any error code returned by validate service. Can anybody help me in that. Here is an example of error returned by validate service

path name - /ISA/GS
error code - VV-003
error message - [B2BCORE.0082.9027] Dimension mismatch, List expected

Can anybody tell me how to populate AK3 and AK4 segment based on this error?

Thanks & Regards.