..snip..
BEFORE doing this, you should change your Visual Studio settings so that it adds MM .NET user interface controls to your form rather than regular .NET controls. To do this, select Tools | Options from the VS menu and select Windows Forms Designer | Data UI Customization. You can then specify to use MM .NET UI controls by default for each data type.
..snip..

Is there a similar requirement w.r.t. to Web Forms? i.e. I don't see a counter-part for the html designer.

Oh, by the way, don't try looking at the Windows Forms Designer | Data UI Customization while working on a WebApp project ... VS (2005/SP1/AJAX RC) crashes.

Thanks,
--dan