[NTG-context] simplefonts: math in headers

hi, i have the following setup: \usemodule[simplefonts] \setmainfont[Cambria] \setsansfont[Ubuntu] \setmonofont[Envy Code R][regularfont=envycoder] \setmathfont[Cambria] \setuphead[section][style={\ss\bfb}] \starttext \section{Wat? $y=x^2$} \stoptext why is the math in the header typeset in computer modern instead of ubuntu and how do i fix it? PS: preferrably it should be bold, too. there is a wiki page, “Bold Math in Section Titles http://wiki.contextgarden.net/Bold_Math_in_Section_Titles” but it doesn’t explain how to do it with simplefonts.