How do I display a folder in a treeview if the folder is empty

Hi
I am using the DirectoryInfo object to retrieve folder structure and populate this into a treeview control.

I have it working but in the style of XPFileExplorer which is fine but the last directory presents as if its a file rather than a folder. If the folfer has files in it, everything will be ok but if the folder is empty the folder displays as though it is a file.

Here is some code that I am using ....

    Private Sub PopulateTree()
        'Populate the tree based on the subfolders of the specified VirtualImageRoot
        Dim rootFolder As New DirectoryInfo(Server.MapPath("TestImages"))
        Dim root As TreeNode = AddNodeAndDescendents(rootFolder, Nothing)

        'Add the root to the TreeView
        Me.trvProd.Nodes.Add(root)
    End Sub

    Private Function AddNodeAndDescendents(ByVal folder As DirectoryInfo, ByVal parentNode As TreeNode) As TreeNode
        'Add the TreeNode, displaying the folder's name and storing the full path to the folder as the value...
        Dim virtualFolderPath As String
        If parentNode Is Nothing Then
            virtualFolderPath = "TestImages"
        Else
            virtualFolderPath = parentNode.Value & folder.Name & "/"
        End If
        Dim node As New TreeNode(folder.Name, virtualFolderPath)
        'Recurse through this folder's subfolders
        Dim subFolders As DirectoryInfo() = folder.GetDirectories()
        For Each subFolder As DirectoryInfo In subFolders
            Dim child As TreeNode = AddNodeAndDescendents(subFolder, node)
            node.ChildNodes.Add(child)
        Next
        Return node     'Return the new TreeNode
    End Function

I would be grateful for your assistance.