i just updated to symbian belle and i confirm too that it's not working unless you have both the wifi ON and mobile data ON. You don't really have to be connected to a wifi service, it will still use your 3G or 2G connection if there's no wifi.  I find this kinda annoying though as wifi as it adds to battery drain when your wifi scanning is turned on, aside from the fact that wifi is not really that widespread here in the Philippines

Device: C6-01
Carrier: Globe
Country / Language:Philippines
OS / Browser / build number (if applicable): Symbian Belle