Integration between external PO, PSFT AP and PC - How to create "COM" analysis type rows?

Integration between external PO, PSFT AP and PC - How to create  "COM" analysis type rows?

At the client I am at,  they have an external Purchasing system, and in house AP and PC . Following are key points:

1. Purchasing is an external system, so there is not a PSFT PO installed, no REQ neither PO data into the common tables (PO_LINE, PO_HDR etc.).

2. Payables data (VCHR) comes from an outside system and a Payment process exists in PSFT, which triggers the PC_AP_TO_PC, to generate the ACT analysis type rows in PROJ_RESOURCE table.

3. Client (via interface ) wants to create the COM analysis type, or commitments rows in PROJ_RESOURCE.  Client have no  BUDGET (KK) module active in this process.