personal hotspot ipad2 3g

I have a iPad2 3g for AT&T service. While living in the USA, the 3G service was never activated. I am now living in Cambodia and have installed a Cellcard SIM card to the iPad with hopes that I could use as a hotspot. However, the Personal Hotspot option doesn't exist. I have tried several things listed on support sites, but nothing seems to work. I just updated to iOS 7.0.2 among many other things include network resets. Any ideas to get this working? Did I need to do something via the AT&T service first before switching SIM cards?