I've found the problem.
When changing font-size in the editor the font gets saved in px.
After saving to RTF everything still seems okay (the font sizes are converted to points, wich i believe is the correct way for RTF).
Then after the RTF gets converted back to HTML (LoadRTF) the font-sizes do not have a pt or px font-size indictator so IE shows it as px (wich is 0.75 times smaller).
I've made a quickfix to add the 'pt' indicator to the font-size tags after the LoadRTF is called and now everything works fine
Regards,
Freerk Jelsma
SchoolMaster BV