PLEASE HELP!!! I am simply trying to update the APN settings on my Iphone3 AT&T carried Straight Talk SIM phone. For some reason, when I enter the Straight Talk APN info in the Config Utility and click "Install", NOTHING HAPPENS. WHY?

PLEASE HELP!!! I am simply trying to update the APN settings on my Iphone3 AT&T carried Straight Talk SIM phone. For some reason, when I enter the Straight Talk APN info in the Config Utility and click "Install", NOTHING HAPPENS. WHY? I have spent almost 2 full days simply trying to get the cellular data network settings to appear and I am now at the point of pulling hair and/or smashing things. Why is it so difficult to simply update the cellular data network APN settings on a standard Iphone 3 ATT with a unlimited Straight Talk plan? Everyone knows that Straight Talk's $45 a month unlimited data/calling plan is supposed to be 100% compatible with AT&T carried Iphones. Will someone please tell me HOW TO UPDATE THE APN SETTINGS ON THIS IPHONE 3. Thanks and God bless

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