Hi RB,
this is what i am doing
i run t code RSA1 and go to source system.
Then right click on SAP and click on create
Then i enter the RFC and user details
Then it pops up in UG1(ECC system ) login screen and asks to enter with admin user
The it pops up below screens
When is click on use i get below error
R3SBP200 being other ECC source already connected to BI system