Hello, Thx Paul, I looked at your website but didn't get anything working :s Anyway I don't understand why it should be a font problem, because in facts it has to font .. It just doesn't use it at the correct moment :S.
I've also noticed that when I leave math mode, I get this error : dvipng warning: at (0,-1) ignored header \special{!userdict begin/bop-hook{/isls false def/vsize 792 def/hsize 612 def}def end}. Does anybody know where is the problem? Thx Esox