Blanket PO Item from Requisitions

Hello All,

We are XA R9. I am beginning to work with the Requisitions object
(REQHDF, REQHDX, etc.) Currently we are writing our own records to the
REQHDF file and I am able to create a basic PO from Requisitions.

Has anyone found a way to code the records and/or configure create
templates in order to create a "hands off" blanket line item? For
example, for vendor A, Item B, need to order qty. 500 and qty. 700 for two
different future dates. There will also be non-blanket items on the PO.

The "Procurement Management Concept Guide" describes a way to do some of
this through the user interface and user interaction. I call this the
"hands on" method. No success for me on that though, when attempting a
Combine in the Create Purchase Order dialog, I get a message "Warning,
cannot combine items related to externally controlled requisitions". Does
anybody how to get around this?

I am also aware that what I am asking about is doable through System Link
transactions. But my manager is not ready to invest in the development
time yet.

Thanks for reading through this. If there some reference to what I am
asking about I would love to know about that too.

Regards,

Tim Carlo, Precision, Inc., Pella, IA