Detecting and firing mouseover events in sfarari

How do you generate mouseOver events in sites? There are sites that will show menus when the mouse is over a given element. In those cases, activating the link won't show the desired menus or make the desired actions occur. In JAWS, one presses ctrl + ins + enter and programatically the mouseOver event is fired, allowing access to the desired content. In voiceover however I have no idea about how to make the mouseOver events occur with pit a mouse. How do you cause mouseover events with vo and safari? Marlon