Hi Leo,
Let me see if I get this right. You have an ECC and when a sales order is being created you want to query one other system, the Pricing Engine, to determine some condition values and what not.
Is it like this or do you want the sales conditions to be updated regularly from the pricing engine?
Both approaches differ a lot but are somewhat similar to what can be done in CRM or any Sales Force App.
There is also a product, SAP Price and Margin Management by Vendavo, but I have no knowledge about it or how it works.
regards,
Edgar