I think you shouldn't use tasks.dll ontop because it's visibility persist in few games or apps that need to run in fullscreen mode...
zorder.dll won't help you anymore. tasks.dll manage z-ordering in a strange way, but you could try to TasksDockWindow ShortcutLS (or something similar) or use labels instead (I know it's working with labels).
Be sure you load the module you want to dock to before tasks.dll
Tips: applying transparency to the module to dock to won't work (except if you use LSTransparent.dll)
Have fun...