Add Prev/Next button to Fancybox

I was wondering if there is a way to add a prev/next buttons to the fancybox (lightbox effect)? I know there is an option to do this within the fancybox plugin – fancybox.net but I tried to implement this and it didn’t work.

Any help would be appreciated.

Thanks!

http://wordpress.org/plugins/nextgen-gallery/