TreeView control - dynamically bind to XmlDocument, not xml file?

[THY02K]

hello

Reading this article on TreeView control...[^], it shows how to either bind a xml file on disk to TreeView control via "XmlDataSource"

<div>
<asp:TreeViewExpandImageUrl="Images/closed.gif"
CollapseImageUrl="Images/open.gif"ID="TreeView1"
Runat="server"DataSourceID="XmlDataSource1">
<DataBindings>
<asp:TreeNodeBindingDataMember="Category"
ValueField="ID"TextField="Name">
</asp:TreeNodeBinding>
<asp:TreeNodeBindingDataMember="Description"
ValueField="Value"
TextField="Value">
</asp:TreeNodeBinding>
</DataBindings>
</asp:TreeView>
</div>
<div>
<asp:XmlDataSourceID="XmlDataSource1"Runat="server"
DataFile="~/Data/Categories.xml">
</asp:XmlDataSource>
</div>

My question are:
1. how can we bind an in-memory (not on disk) XmlDocument object to a XmlDataSource? and thus TreeView control? In the article author has suggested an alternative - OnTreeNodePopulate event - however, this is not suitable for my case as my whole list/hierarchy is loaded in one go, not once-per-node.
2. how can we set navigation Url? in standard "web.sitemap", you can do this with siteMapNode's "Url" attribute. But now that, as in above example, uses my own custom Xml... how do we do this?

Thanks