Add next/prev buttons to Wordpress NextGen ScrollGallery

I have wordpress nextgen scrollgallery. I need to implement next/prev buton on this gallery. Next/prev buttons are inserted into html, but they are not functionaning. You can overwrite plugin code. I won't update it later. I need some very quick hack. Plugin uses MooTools that opereates on image and thumbnails ([login to view URL] in plugin folder). I believe that you have to modify scrollGallery.js. This should be quick fix if you are familiar with technologies. Max 1 hour to work. Bid if you can start in 3-4 hours and only if you have knowledge.