Not sure about the XML file you have specified. But you can achieve the same results by using the web.sitemap file.
You need to set ShowStartingNode="false" on the sitemapdatasource control. For example:
web.sitemap file
----------------------
----------
--
http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >
title="Dashboard" description="" />
.aspx page
----------------------
------
Menu ID="Menu1" runat="server" DataSourceID="SiteMapDataS
ource1">
Hope this helps.