UISCrollBar Component. Custom "thumb" size?

so i’ve customized all the icons in my scrollBar component successfully… sort of.

the “thumb”(sliding area) is resizing so large that the new icon that replaced teh bar only moves a very small amount.

anyone know a way to either turn the scaling of the thumb off, or to scale it down? basically i need to modify the code that does that part of the component :?

any help appreciated.