Not sure if I understand your question correctly but you should be able to go into the communication manager and tap the switch on data connection. This will shut off your data until it is needed again, ex: if you go into opera then it should switch back on.

Quick link to communication manager, not sure on your ROM, haven't used it, would be to tap the upper bar on your phone, where your battery is displayed and all those other icons, then tap the icon next to "Carrier Name" also has a counter depending on if you have a active data connection.