Difference between BAPI_POEC_CREATE vs BBP_PD_PO_CREATE

HI,

I need to create a program to create purchase orders in SRM 5.0 Extended Classic using an input file instead of manually creating 50 plus line service purchase orders with MAA. .

I've read numerous posts on the topic and now I'm more confused than before I started. I was under the impression that I need to use the BBP_PD_PO_CREATE function instead of BAPI_POEC_CREATE. In one of the posts it said that the BAPI_POEC_CREATE doesn't apply to extended classic.

What is the correct approach?

Thanks,

Jerry