Bendix pads are sintered. Sintered aren`t good for Cast Iron(as you are finding out), apart from wearing them down faster, they also are prone to rust/bind onto the disc when they get wet. So unless you don`t plan on cleaning the bike after each ride...
I`ve heard the best ones to use are Ferrodo Platinum pads
[Edited on 15-5-2003 by Desmoboy]