Need to select my own subinventory while doing the Allocation Process

Hi All, I am working on R12.
I am doing the Customization for Pick Release for all EAM Work Orders.

I am currently calling WIP_PICKING_PVT API manually which creates the Move Orders. (i.e. Allocates and Pick Releases)

My Requirement would be to suggest a subinventory while doing the allocation process. I guess the engine takes care of this in the standard process, (Correct me if I am wrong).

Is there any way of achieving this?

Any hints would be appreciated.

Thanks and in advance.

Jacob C