yep, when you disconnect the battery, the HU will be reset. Thats how its supposed to be. Now if you turn you key off, and the radio resets, then you indeed have the memory wire not seeing power. So if you HU keeps memory with the key turned off, then you are fine.

13.5 @108 MPH-2.2 60ft(stupid FWD!)
S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential
fuel injection)
My webpage: http://eclipsed4evr.home.comcast.net
-1998 Mitsubishi Eclipse RS-T- "Toy"
-1992 Plymouth Laser Turbo AWD(SOLD)
-2000 Honda CR-V(daily)