I took a different direction with a carousel I implemented, opting for bxSlider instead of jCarousel. This is for an image gallery I am building http://rjwcollective.com/equ
You should play with these two - destroyShow() and reloadShow(). My guess is using reloadShow() only but if it doesn't work out try destroyShow() followed by bxSlider(). You'll need a variable as a reference to the plugin api.
var slider = $('#thumbs').bxSlider( { ... } );
slider.reloadShow(); // or slider.destroyShow(); $('#thumbs').bxSlider( { ... } );
Good luck