My problem at the moment is that I long press 'play&pause' the iPod shuts down then 3 seconds later switches itself on again.
So now, when immediately the iPod goes off I flick the hold button to 'on' & after about 7/8 seconds the iPod changes into Apple iTunes mode then I can shut down as normal. To switch back to Rockbox I press select than reboot & I'm back in Rockbox mode.