The new Alpine I have does not act exactly like the stock unit. With the stock unit I was able to listen to the radio/CD with out the key in the car.
With this unit I must have the key in and in the Aux power or pre-start position. But the unit does remember what mode it was in when I power the car up...........also Reg I tested the units power switch, and it also does
remember what mode it was in when switched off. One differance between your set up and mine, and I would not really expect this to be the problem, is that I am not using the XM radio feature.