TreeView in asp:Wizard

[yonibit]

I'm placing the treeview inside  "asp:WizardStep" and I keep getting "Object reference not set to an instance of an object.".
In one post I found trick to add the tree in panel and add the tree and the events to the panel in "Page_Init".
<asp:Wizard ID="Wizard1" runat="server">
                <WizardSteps>
                    <asp:WizardStep runat="server" Title="Step 1">
                        <asp:Panel ID="Panel1" runat="server">
                        </asp:Panel>
                    </asp:WizardStep>
            </asp:Wizard>

This trick work only if the ExpandMode of the nodes is "ServerSide" but not if the ExpandMode is "ServerSideCallBack"

You can read an old discussion at
http://64.233.183.132/search?q=cache:AkaVFLOkCRwJ:www.telerik.com/community/forums/thread/b311D-mdbcm.aspx.aspx+RadTreeView+asp:WizardStep&hl=iw&gl=il&strip=1