[jQuery] Superfish - negative margin on hover in IE

[jQuery] Superfish - negative margin on hover in IE


I would like to put a negative margin on the hover of the LI's in a
superfish jQuery menu on a vertical menu. When I do this, in IE on
the hover, the elements go below the rest of the menu. It's fine in
Firefox.
Here's my starting code:
/*** adding sf-vertical in addition to sf-menu creates a vertical menu
***/
.sf-vertical, .sf-vertical li {
    width:    211px;
}
/* this lacks ul at the start of the selector, so the styles from the
main CSS file override it where needed */
.sf-vertical li:hover ul,
.sf-vertical li.sfHover ul {
    left:    211px; /* match ul width */
    top:    0;
}
and I'm just adding this:
.sf-vertical li.sfHover ul {
    left:    211px; /* match ul width */
    top:    0;
margin-left: -20px;
}
Or even:
.sf-vertical li.sfHover ul {
    left:    191px; /* match ul width */
    top:    0;
}
Both do what I want in Firefox, but there seems to be a z-index issue
in IE....
Help?