Migrating from Microsoft.Web.UI to System.Web.Ui - TreeView Control

Hello,
We have an old web project built in NET Framework 1.1.
It uses the TreeView control which is related to Microsoft.Web.UI library.
Now I would like to replace this old, obsolete control by the new one, from System.Web.UI
However there are some functions that I don't find the replacements for.
Ex: This control is populated dynamically from XML file.
<TREENODETYPES> <TreeNodeType type="employeur" SelectedImageUrl="Images/ico/18_service.gif" ExpandedImageUrl="Images/ico/18_service.gif" ImageUrl="Images/ico/18_service.gif"/> <TreeNodeType type="file" ImageUrl="Images/ico/ico_16_1039_d.gif" ExpandedImageUrl="Images/ico/ico_16_1039_d.gif"/> <TreeNodeType type="folder" ImageUrl="Images/ico/closedfolder.gif" ExpandedImageUrl="Images/ico/openedfolder.gif"/> ...