Isn't it nice how Microsoft never tells you why you can't edit certain options?
Here's how you can change from HTML E-Mail to Plain Text in Outlook if the options are greyed out.

Open regedit and go to
HKEY_CURRENT_USER\\Software\\Microsoft\\Office\\11.0\\Outlook\\Options\\Mail

Here change EditorPreference to '65536'. Et voila, finally sending all mail in a sane format.


EOF