scale9grid for scrollbar thumb?

[Yui]

Hello,

I'm having troubles scale9grid-ing the thumb of a scrollbar, it just seems to not working. i'm using scaleGridLeft/Right/Bottom/Top properties in the CSS file, but the top and bottom are getting distorted (they disappear completely) when the thumb gets too thin.
I'm also intrigued by the fact that the scaleBottom must be greater than the the scaleTop, same for left and right. why can't they have the same values?

does anyone have any idea of what goes wrong? or any alternate solution?

thanks in advance.

[mattb]

What kind of file are you embedding? If it's an SWF there are some restrictions you need to be aware of concerning the internals of the symbol you're trying to apply 9-slice scaling to.

Can you post the CSS line you're using?

[Yui]

It's a .png image, but if there's any other format that can help me solve this problem, please do tell.