Find "Voice server number"
Press the Navigation key.
Scroll to Messages and press the Navigation key.
Scroll to Settings and press the Navigation key.
Scroll to Voice mail number and press the Navigation key.
Scroll to Voice server number and press the Navigation key.
Save voicemail number
Highlight the top menu item and press Options.
Scroll to Edit and press the Navigation key.
Scroll to Change name and key in the required name.
Scroll to Edit number and press the Navigation key.
Key in (prefix) 5 (your phone number) and press Options.
Scroll to Save and press the Navigation key.
Exit
Press Disconnect to return to standby mode.