[Plugin: Slideshow Gallery] gorup images in thickbox

This is a real nice plugin however, when the main image is opened in thickbox, I cannot navigate when the image is in the lightbox.I want to be able to click through the images in the lightbox. It must be a very simple fix to add either class or rel but I have no idea where to add it.
please help.

http://wordpress.org/extend/plugins/slideshow-gallery/