iPod How do I shut-off iPod Mini instead of sleep?

I have the last generation of the iPod Mini before it was superceded by the Nano, and I have recently had trouble turning it off. It seems that when I hold the pause/play button for several seconds, it goes to sleep instead of shutting down. I have the "sleep" setting in Menu turned to off but this has no bearing on the outcome. With my iPod completely charged, my iPod drains to near nothing in a matter of days without ever being played because the unit is sleeping instead of completely shutting down.

HOW CAN I SHUT THIS IPOD DOWN/OFF COMPLETELY SO THAT A REBOOT IS NECESSARY WHEN TURNING IT BACK ON???

Any suggestions is greatly appreciated. Thanks...

Lock Switch doesn't help...

Thanks balamw:
I forgot to mention that this is SOP (standard operating procedure) but it doesn't make any difference if the lock switch is set or not. It can set idle for an hour or a day or a week and as soon as I unlock the switch it immediately lights up at the last song that was playing (if any battery juice remains). I haven't seen a reboot now for several months. I tried resetting the iPod to default settings a number of times. Nothing works.

Thanks to all that replied. I will look for an update as I am sure my iPod will need to shut-off at some time. Anything within 24 hours is certainly better than never. I sometimes go a week or two between listening to my songs and it is a pain in the arse to have to charge the iPod each and every time I go to use it. Thanks again everyone.