USER EXIT or BADI BY MIGO

Hi to all

I need do it a validation in the transaction code MIGO, by the serial numbers.

For example: When I put 5 in amount, appear 5 serial numbers, and I need validate that all de 5 fields of the serial numbers.

Which user exit, or badi I have to use by do it this task ?

Tnak you very much

regards

Dario