Static sidebar within div

Hey guys,

I’m working on http://new.xpient.com/blog/ with a twentyten child them.

I want the sidebar on the blog page to be static and stay where it is when you scroll through the blog entries. I currently have it set position:fixed. However this is affected by external scrolling. Can someone help me with a way I could fix this to be unaffected by scrolling outside of the div?

Thanks