RFC in B2B

Hi,

i am kind of a newbie and i am trying to connect an external system to th XI.

Its an 4.6c System so i can't use Proxies instead i use RFC.

I am a little confused how to configure the R/3 System and the XI-System.

R/3:

so far i understand that u need...

- a RFC-Destination type 3

- a RFC-Destination (RFC_Adapter) of type T with a registered Sever Progamm identified via Programm ID. But whats this Programm ID, is it just an identifier i specify in the Integration Directory? Or is it a real Program?

- a RFC-Destination of type L as a Reference to the RFC_Adapter-Destination

...so far i read in the documentation!!

Everything mentioned i have to configure in the R/3-System because its the sender-system - RIGHT?

Some other questions in my mind:

What do i have to configure in the Integration Engine? Another RFC-Destination?

Do i need to put the external-system in the SLD - i think NO because its a B2B-Scenario and i don't know the external system-landscape!

What to configure in the Integration Directory because its a B2B-Szenario, do i need a Business-Service?! How to configure a Business-Service?

I would appreciate ur help, thx!!