Is there any way to set iPhone wallpaper programmatically in iOS 4.2 (beta)

Question

I know this question has been asked before, but does anyone know if its possible to programmatically set the background image for the home screen (wallpaper) for the latest iphone OS iOS4.2 (beta). I know it wasn't possible before.

I've seen that you can change the lock screen on a jailbroken phone by writing to /var/mobile/Library/LockBackground.jpg, can you do the same for the home screen wallpaper?

Follow up: as the commenters pointed out, iOS 4.2 is under NDA, so I rephrase the question for 4.1?

Answer 1

No. And are you sure it's in /var/mobile/Library??? When I do

    NSArray *test = [[NSFileManager defaultManager] directoryContentsAtPath:@"/var/mobile/Library/"];

I don't get a LockBackground.jpg file. Also, You can NOT write to /var/mobile/Library (using writeToFile:atomically:)

Note: I am doing this under 4.1