Dear Sjaak,
I have some questions about the Self Service Procurment Portal, I hope it's still on-topic 
1: Does the Business Function need a java stack, as it seems to use a portal
2: How can I change the BRF rule, that it creates a PR or PO directly?
3: How can I quickly change the standard workflow to test the fuctionality
Hope you can answer these questions.
Regs,
Ruud