I looked at some pics of the SRAM 3.0 and it is similar in construction to the newer Shimano "Shadow" derailleurs. With this style of derailleur, there is no spring at the mounting bolt pivot location and the B screw simply sets the location of the upper pulley in relation to the cogs. You can usually identify this style of derailleur by looking at the cable entry point. Shadow style derailleurs do not usually have the large loop of cable that enters from the rear. The cable entry point allows a straighter run of cable housing without the loop.