How do I save my movie as an MPEG-4?

I would actually like to save my movie as MPEG-4, however, that option is not showing up in the drop down.  How do I change the format to MP4?

<Split from thread:  http://answers.microsoft.com/en-us/windowslive/forum/moviemaker-wlsettings/why-is-my-movie-maker-outputting-mp4-instead-of/f3043874-683d-4dd1-97c2-bd194da6c075#LastReply  >