Web GoOverview Problem

Hi all,
I am having a small problem with my Web based GoOverview control, We set the observed state to that of the GoView each time the page loads, however when we call GoOverview.RescaleToFit, the GoOverview goes blank (it looks really zoomed in).
We have two buttons on our page, each performs a different layout algo, the second of which shows a substantially larger number of nodes in the view (hence the overview window must be changed to fit). I don’t think it is a problem with LimitDocScale, as when we try and go back to the first view (which is displayed - on entry to the program) that too is also invisible. If we don’t call rescale to fit then when we change views, both views are displayed in the GoOverview however the larger of the two layouts is “chopped” off and we have to scroll around the GoOverview (which isn’t allowed in our app)
When the page is first loaded and the session state started, we call a Rescale to Fit on the overview and that seems to work well. So essentially any subsequent calls to rescaletofit in the life time of the Overview don’t seem to work correctly.
Are there any hints, tips, futher guidelines that you guys might know about.
Regards
Paul