Anyone here using Digi 3G on their iPhone?

After updating carrier settings via iTunes, it gave me the internet tethering function but I can't seem to edit Cellular Data Network settings anymore, and now I can't use MMS.

Anyone have any idea what can be done?

i'm on the Digi 3G Unlimited Data plan @ RM 48 per month (since I registered last year). it's quite flawless when using Internet tethering on my iPhone 3GS at open areas or in my house near the windows. the only thing is, Digi needs to seriously improve on their indoor coverage as once you are inside a place with many walls, the connection really drops.