Heh-heh....
Throw the Eurovox in the bin and fit something else!
(sorry Mate, just kidding)
I really don't think there's anything you can do without some modification of the head unit.
(I have a VZ, and the Blaupunkt has no remote or low level output either - I'm in the process of modding that unit to drive/switch my power amp)
The only thing I might suggest is a switch on the dash or console somewhere that's wired from the accessories circuit through to the amp's remote terminal.
(that way, even if the switch is left on, the amp will power down once the key is turned off)
Cheerz!