Concept of Free Goods in Scheduling Agreement ?

There are two line items with same material but different quantities.

The user has given a price for both and created a SA.

Then the user comes to know the line item 2. is free goods.

So then he/she wants the net price of line item 2. to be zero.

In order to do so, the user went to item conditions and entered PB00 condition type as Zero value.

This was saved but the user was unable to do GR.

I tried to use Net discount condition type and gave 100%, it din't help to do GR.

I tried to create a condition record with free goods, it din't flow in SA, but it works with PO.

So guys, help me with this !!

Warm Regards-

Bharath Anandan