Shipping issue

Dear Guru's,

I have this issue, i created a Sales Order, then delivery was created and the quantity was picked and packed....The material that i am using is BATCH managed...

now i go to VT01N and created a shipment..... I enter a PLANNING DATE, and SHIPMENT COMPLETION DATE for execution. and everything looks good till now, i hit SAVE button.

*But the issue is, PGI is not getting done,* when i go back and check the Shipping document i cannot see the SHIPMENT COMPLETION DATE checked......and so no PGI can be done, could you please tell me what might be the reason???

Thanks

Nidhi