How do you put a password lock on all the time on a LG Xenon?

I found out how to put a password lock on the LG Xenon, but I want to do it all the yime. Every time I have to unlock it. Not just every time I change the SIM card, or every time I turn it on, all the time. How do I do that?How do you put a password lock on all the time on a LG Xenon?
That exact issue came up at work on Friday and we went thru every type of password; PIN code; etc that is in the device tutorial for that device and none of them work as a permanent lock like you want. You might want to call LG and see if therre is a way that is not published