Wait, hold the phone. What happens when you just press K? If you have the 4.2 O.S a few things have changed. I use to be able to do ALT & L, and it would lock, but now I just have to press K (not hold it, just press it!)
Well. If you press K is locks everything and the screen goes into a locked mode. I was hoping that I would still be able to see my email coming in or scroll through a webpage.
Ah, you want the best of 'both worlds', like a partial lock. Sorry, that's not going to happen.
Further more, if you think about it, you lock it, 'your way', and put it in your pocket. That means it can scroll through a webpage on it's own, in your pocket, by accident.
Now most people have unlimited data so that would not matter. But, am sure you get my point...