Nokia Phone - how do I set up my phone to divert all my calls to voicemail?

[dancingtina]

I know to go to settings then divert all calls but then it asks for a 'mailbox number' - how do I know what my mail box number is?

I'm with O2 if that's any help.

Thanks

Is this any help: O2 . I'm not on O2 unfortunately.
Cheers
mj