Originally Posted by Myst3ry (Post 1487268)

I'm PRETTY sure this should work, but i think the wallpaper you use for your windows start thing... SO... go to Settings>Today and at the bottom where it says "use this background" choose that and it should change your lock screen background (but also your windows start menu background)

It works for me, but i don't know if it is ROM-specific or not...