Although this is not recommended by W3C, out of popular interest, i feel like posting the solution to this problem. The problem, being the fact that IE went ahead and allowed people to customise its scrollbars, while the gecko browsers like Firefox, Opera does not allow user styles to custom browser styles.
For IE scrollbar settings, you can use the following properties:
For Gecko-browsers, you can use the FlexiScroll. Its free for commercial use:
Hope this helps!!