Found out that the issue is with asp.net
Quote from asp.net forums as for a working solution (works for me) http://forums.asp.net/p/941229/2581789.aspx#2581789
QUOTE>
Hello,
maybe I can help you all with this issue as well. What I did to enable the asp:menu for Safari was to add a file called safari.browser to the App_Browsers folder. The contents of safari.browser are as follows:
<browsers>
<browser refID="safari1plus">
<controlAdapters>
<adapter controlType="System.Web.UI.WebControls.Menu" adapterType="" />
</controlAdapters>
</browser>
</browsers>
Basically the refID matches a browser id in the original browser configuration files for the .Net framework. In our custom .browser file we override the control adapter settings for the asp:menu control for this specific browser.
There's one catch. Safari will crash when the browser window is too small to contain all the items in the menu and you hover over then out of the menu. I can not confirm this is true for Safari in general, but I have consistently seen this behavior on a Mac with OS X 10.3 and Safari 1.3, so be sure to test this case. This might be the reason that Microsoft decided to render an alternative menu for Safari.