iOS 3.1.3 and the "Cellular Data "On-Off" Button

Here's my problem, I recently acquired a iPhone 3G (not an 3Gs) and Downgraded from iOS 4.2.1 to 3.1.3 and after doing so I noticed the On and Off button for cellular data from the Network menu is missing and from what I understand it's a iOS 4+ feature. MY QUESTION. Is there anyway add it to 3.1.3 I've tried many of apps and SBSettings has worked so far but it doesn't shut the data off completely, It only changes the APN to 127.0.0.1 and the phone searches for internet, The reason I am trying to do this I had significant battery life when I used this option on 4.2.1 So is there a way to do this with PLIST files or something?

Any help will be greatly appreciative.

 

That isn't an option I refuse to upgrade, I can't deal with that lag.