Negative Margin and Overflow? [RESOLVED]

Hi,

I have a design at nubornis.com/test that I'm working on. All the CSS is contained in the actual HTML document for now. The problem I'm having is that I've given the div with the ID a negative left margin (-20px) but in IE it gets cut off. I tried modifying the 'overflow' attribute of the div with ID wrapper to visible but it doesn't make any difference. Does anybody know how I can make the surrounding div not cut off the menu div?

Thanks in advance, Tom