Pdirect,
I'm going to assume that you are formatting the text in our text editor. I just tested it out and it seems to work. The next time before sending an email click the HTML tab at the bottom of the editor and let me know what you see. You should see something all the lines of the following
<p>This is a test in Arial</p>
<p><span style="FONT-FAMILY: Times New Roman">This is a test in Times New Roman</span></p>
<p><span style="FONT-FAMILY: MS Sans Serif">This is a test in MS Sans Serif</span></p>
-Michael