o2 My Europe Extra - Incoming charges for voicemails?

[inquisitor]

Originally Posted by ronwi

I would be shocked if the voice path to the voicemail box was actually home country to roaming country back to home country voicemail. It makes more sense that if there is no answer/busy in the roaming country, the call path from the home country to the roaming country is terminated, and the call simply goes directly to the home country voicemail without being routed through the roaming country.

Actually it is as you fear. if you have set up a conditional diversion to your mailbox, your home network (rather the HLR) will forwared incoming calls to the roaming network and only there it can be determined, if you're available or not. If you're registered the call is being connected and your phone rings (single roaming charges apply), if not the call is reforwarded to your home network (doube roaming charges apply) again.
You can evade this only by setting up a permanent diversion, so if you can't abandon your mailbox, just set up a permanent division to it, before you switch off your phone.
Btw to delete all diversions enter ##002# and pick up.