Please refer to our Custom Scrollbar online demo - http://demos.telerik.com/aspnet-ajax/slider/examples/customscrollbar/defaultcs.aspx. It demonstrates how you can use the RadSlider control in order to slide a DIV element.
I am not sure how you intend to change the zoom level. However, basically, when you change the zoo
m level, you should simply change the size of the viewport element - the "boxes_wrapper" element in the Custom Scrollbar demo.
the Telerik team