cash management for intercompany stock transfer process

Dear,

my company plans to use intercompany stock transfer process to replace normal PO-SO-DN-Billing process. we will create PO with delivery plant as vendor, create DN against PO, and billing.

now i have a problem on FF7B. usually when we create PO and EDI to a SO, we can see open SO on FF7B as level S1.

for this new process, there is no Sales order. so i can not find it on FF7B (cash forecast management report) then the report is not right until the billing is created.

do you know how to solve it? does SAP have some standard process on it?

thank you~~

Liu Min