Use:

*61*1234567890# Call Forwarding No Reply (AS NOTED ABOVE)
*62*1234567890# Call Forwarding Not Reachable
*67*1234567890# Busy Call Forwarding

Then to cancel

##61#
##62#
##67#

No promises folks, but I am PRETTY sure this is how to setup your cell number so it forwards to Google Voice. Voice mail forwarding is working for me, but I can’t remember exactly what I did.

These numbers were provided by the commenter “Ryan” on the clicksandbits.com site.