Well shirt pocket is awesome, customer support answered my question tonight which was great (nearly 10 pm eastern). Using 2.5 upgrade and 10.5.2 on my iMac it is now doing a BU on my USB external drive connected to my AEBS. Because this should be bootable, I prefer it greatly to TM which is not bootable. I don't do enough work on my iMac during a day to make TM really payoff. I want bootable copies for when my drive makes smoke. This seems to me like a great solution with evening backups.
Thanks Shirt Pocket and SuperDuper!