I'm updating our Umbraco version from 7.6.1 to 7.12.4 and I'm looking for help upgrading the Trees for our custom Sections.

The custom Trees are based on BaseTree and I followed instructions on upgrading them to TreeController. However, the targets in the legacy sections as based on MVC which start by calling a MVC controller, where as the TreesController and CreateTreeNode method targets a specific html file and Angular takes it from there. Our existing Trees use the Render and RenderJS methods to trigger calls to the MVC controllers (which don't fire anymore, and I know from the upgrade guides they won't) and this is an edited sample:

    public override void RenderJS(ref System.Text.StringBuilder javascript)
    {
        javascript.Append(
            @"function openConnectionsCustomerServiceController() {
                UmbClientMgr.contentFrame('/umbraco/backoffice/plugins/customerservice');
            }");
    }

    public override void Render(ref XmlTree tree)
    {
        RenderNode(tree, "3", "Customer Service", "javascript:openConnectionsCustomerServiceController();", "folder.gif", "folder_o.gif");
    }

Could I ask for a push in the right direction for updating the Trees to do something similar? Unfortunately I can't get the time (management!) to upgrade the Sections to Angular. Any help is greatly appreciated,

Drew