Linking to an anchor point in a framed page.

I am using an image as a link, which has an 'onMouseUp="MM_openBrWindow' behavior attached.
The newly opened window (named; 'help') uses frames.
I would like to link to an anchor tag contained within the 'body' frame.
I can get the 'help' window to open fine but cannot get it to open at the anchor tag.
Any assistance would be greatly appreciated.
Regards.