How to get MMS to work with an iphone 4? Carrier: straight talk?

I have an iphone 4 under the Straight Talk service. I have an unlocked, unjailbroken iphone with iOS 6.0.1 update with a straight talk sim card in it. I absolutely love the service, it's so awesome, but the ONLY downfall is that I cant send or receive pictures from anyone that doesn't use imessage. Does anyone know how to enable it without jailbreaking it? I DO NOT want a jailbroken phone, AND i do not have access to a TMOBILE sim card, so please help me! Pleasepleaseplease i'm begging!

Added (1). ALSO, this happens with most iphones. I called about imessage, that's not the issues.everytime i try to send a picture to someone without an iphone it says delivery failure… I want successful delivery! Haha so please help me! Steps please!

This is an issue with iMessage, not your phone setup. Create and attach an AOL Instant Messaging (AIM) account to iMessage to be able to send MMS messages to non-iMessage users.

So, how do you do that?