Attach document while Goods receipt in MIGO

Hi,

Can I attach a word or a pdf document while posting Goods receipt via MIGO.

In 'Service for Object' the option store document is not possible. It is grey out.

Do I need to do some settings to get this option so as to upload a file while posting the GR.

I am able to get the option while create/change PO but not in MIGO.

Regards