OT: Bizztalk vs. XI

Dear colleagues,

One of our customers is using Bizztalk as primary integration plattform but they are also using XI - but not in all branches. However, my knowledge about Bizztalk is very limited and the official Presnetations say it can be connected to SAP - who wonders. Anyways, Did anyone of you a Bizztalk implementation and could tell me how simple or complex it is to have

- IDoc

- RFC

(or others)

connections from Bizztalk to a SAP system (6.40)?

Thanks a lot!

Best Regards,

Jens