Can't enter the new created condition type to the PO

Dear SAP Community,

I created a new condition type ZBA2 by copying the old condition type FRB2 with M/06.

And I maintain this condition type ZBA2 in the calculation schema with M/08.

Now it happens the weird thing:

1) when I create a sales order, which creates a BANF, and from the BANF I create a PO.

I want to add the conition ZBA2 to the PO, by manually entering in the condition tab of the PO.

I write: ZBA2, amount 8 Cent, press Enter. The condition type disappeared!!! No matter how hard I try, it disapears.

The PO doesn't want to take my ZBA2, even though it's a copy from FRB2...

I try the same with FRB2, after pressing Enter, it's shown on the PO as normal.

2) If I doesn't create the PO from the BANF and SAles Order, it works for both ZBA2 and FRB2.

Could you please help me.

Thank you very much!!