[OnMouseOver only firing over series graph]

Hi

I'm using the following on server-side:

Chart.AllSeries.Link.OnMouseOver = "onPointHover('%x')";

This generates javascript mouseover events, calling my onPointHover function with the value of the X-axis.

Works great, but only while hovering over actual chart graphic (eg. the coloured Area or Bar regions).

How can I make it fire while hovering over any part of the chart?

Any help much appreciated.

Thanks