IE6 doesn't support position:fixed at all.
The best you can do without script (or very complicated hacks) is to let iE6 have position:absolute instead and let it scroll with document.
Just place it before the fixed rule and ie6 will use what it knows:
position:fixed;/* everyone else*/
You should also use top:200px rather than margin-top:220px as margin will rely on the elements position in the flow before it is offset whereas as top will place it there no matter where it was.