Trapping F10 key in Navigator

I am working on web pages that work with a plug-in (Neuron) to deliver CBT over an intranet.  The CBT within the plug-in uses the F10 key for several interactions.  I am running the CBT within Netscape Navigator (currently v 3.01, but we may soon move to 4.04).  The window is opened from another web page, using the following javascript

     var myDocHref=window.open('LoadCBT.htm', 'neuronwindow','toolbar=no,status=no');

This creates a Netscape window with only the titlebar showing, and the plug-in window in the middle of the page.

The problem is, when the user presses the F10 key, this activates the system menu on the title bar (the little Netscape icon on the left side of the titlebar).  If the user presses F10 again, the plug-in receives it and the CBT can process it.

Is there anyway I can deactivate the system menu on the titlebar?  I know that I can hide the title bar using signed scripts (in Netscape 4.04), but I don't think we can implement that functionality here.  Is there any other way that I can prevent F10 from activating that system menu?

I'm just talking about Netscape Navigator here.  Also, let me know if your solution works in v 3.01, or just in v 4.04.

Thanks.