jCarousel vertical - need help with multiple columns

jCarousel vertical - need help with multiple columns

Hello,

I'm using jcarousel to vertical scroll thumbnails. Until there, no prob, except that my column doesnt contain only one item, but three, meaning I got 3 columns to scroll at the same time.
It's scrolling ok, BUT doesnt stop when I reach my last item, I can still click on the down button several times (because the script counts the number of items, and doesnt divide them by the number of columns I guess)

Can someone tell me when I can add this in the code comming from the script :
http://sorgalla.com/projects/jcarousel/ ... tical.html

Many big thanks !