How to take a screenshot with my iPhone with broken lock button on ios 5.1.1?

My iPhone 4 lock button has gotten stuck and I'm unable to take a screen shot. I know that on ios 6 you can get the screen shot option on assistivetouch. Unfortunately i'm on iOS 5.1.1 and I'm not looking to upgrade because I don't want to lose my jailbreak. Is there a jailbreak tweak that can take a screen shot without using the lock button?

As far as I know, Assistive Touch on iOS 5 also supports this feature.

If it doesn't though, you can install Activator, and use that to set up an action to take a screenshot. Assigning toggling the mute button twice to this may be the easiest option.

Plus, if you wanted to get that lock button fixed, a repair on it shouldn't cost any more than £30.