Create your own TWiki MoveableType design by attaching your Moveable Type css and images (and a copy of base-weblog.css) to your copy of the MoveableTypeSampleDesign topic. Then configure the settings on the topic to match, so that you can Proof your design.
Enable this design
Copy and paste the following section to your %USERSWEB%.TWikiPreferences topic (or WebPreferences, or your personal topic)