I've experienced this issue after I updated to iOS 6, here's the scenario.
1. Before the iOS update- Blackberry 9220 phone can connect to iPad 3 hotspot and browsing is a breeze, twitter, whatsapp, browser working perfectly
2. After the iOS 6 update, Blackberry 9220 phone CAN connect to iPad 3 hotspot BUT everything, twitter, what's app, browser no longer function.
To test, I connected my BB9220 to an iPad & iPhone hotspot that is not yet updated to iOS 6, and it works fine. So, that's it, thank you and regards 😊