For those new guys working with DNN and trying to have the default DNN menu play nice, I have compiled a number of references that help you get going. dnnNAV is a very powerful menu.

The author of the menu code (Jon Henning) provided us with a nice video tutorial on the CSS characteristics of the dnnNAV menu. A must see. Second you need to add the following code to the menu:

At the top of your (.ascx) skin:

<%@ Register TagPrefix="dnn" Namespace="DotNetNuke.UI.Skins" Assembly="DotNetNuke" %>

In the menu code:

<dnn:NAV runat="server" id="dnnNAV" ProviderName="DNNMenuNavigationProvider" >
        <CustomAttributes> <dnn:CustomAttribute Name="RenderMode" Value="UnorderedList"/></CustomAttributes>
</dnn:NAV>

Of course you can supply other properties as well. Note: you can’t use the CustomAttributes in a HTML skin.

You can find a sample skin on codeplex. This skin does not have the UL feature.

Forum post referenced here.