I'm new to WebFocus as well but I do know that we also wanted to access multiple datasources. We've found that we need to add code to a file that is created with the master. Someone more technical may be able to explain the reason why but I know this has worked for our shop.
For each master created a second file .acx is created in the same directory as the master. Open this file in notepad and add the SERVER= line to your code..... with your information.......
SEGNAME=GLACK ,
TABLENAME=AFS.GLACK,
SERVER=DBADEPT,
KEYS=0
,$
Hope this helps and if I've stated anything incorrectly maybe someone else will jump in and correct me.....