This post may be better off in the Wish List forum, because what you're asking for would have to be implemented in the player software itself. Hijack can't change playlists because there's no IR code for "next playlist" or "previous playlist." Hijack can't actually reach into the player application's space and figure out what the next playlist is or anything like that.

[Ugly hack warning]
1. Send down IR code to select playlist menu
2. Send long down IR code to select current playlist
3. Send right button code to select next playlist
4. Send select IR code
[End ugly hack]

Only works if you selected a playlist originally (not if you hit down,down,down). You could do it with a standard IR remap. Works best if your playlists are flat or nearly flat.

-Mike