scrollbar GUI Skin problem

I have a scrollview and I wanted it to have my own scrollbar images on it. I made a GUISkin and added them to it.

I have a GUI.BeginScrollView object and I end it with calling "interfacestyle.verticalScrollbar" This way the background of the scrollbar gets the right image but the bar itself is still black. What to do?

interfacestyle is the name of my GUISKin.

If you need more information, please tell me.