Serial number for Mvmt type 103

Hi,

We have one scenario we have actvated serial number profile as we want to use Bar code for inventory.

We want to activate serial numbers mandatory for mvmt 103 also. Our Process is like this

Created PO for 50 nos for material x.

Done Migo 103 for 50 nos.

we have z programme through which we will assign all bar codes to corresponding material with serial nos.

but at that time we found only 48 items received as we could do bar code scanning for 48 items

then we will do final GR mvmt 105 for 48 nos.

But here i am not able to mandate serial no for 103 mvmt. and even i click create automatic it is not creating serial no for 103 mvmt document.

Pl help

ASAP

Thanks.

Prasad