Updating Vendor of Freight Condition Type in STO

Hi,

I am facing a problem in updating KOMP-LIFNR in my program. I have below scenario

I have created a Z program which gets all materials from mchb and creates a STO order thru a BAPI_PO_CREATE1. Anyway STO is getting created but i am facing a program to update a freight condition type. I need to LIFNR(Vendor) in freight condition type.

Pls help is how to update is there any bapi to update.

Regards,

Sreekanth