Traveler fontsize html

When a user uses normal text the fontsize is 10, if he uses ‘other’ symbols, bold, etc the mail is html, mime 1.0 and the fontsize is 12, encoding utf-8. This does not seem to respond to the mimecharacter settings, I set english, utf-8 and western to 10.

Is it possible to get it in the same size as normal text, 10?