I just wanted to let you know that Microsoft has released
Windows Media Encoder 7.1 which can now encode to WM8! So
there's no more need for the command-line encoding-utility.

The good thing is, that you can also use the WM8 codecs
with Vegas: simply choose "render as" Windows Media Video
and you will find the codecs in the pull-down-menu (of
course you need to install the WMEncoder 7.1 first).

The question that remains is why they call it Encoder 7.1
instead of 8.....