[NTG-context] Textfont in math-formulas?

Hi There, I have a little problem with fonts in my document. I use the cm sans serif font in my text and want to have this in the tex-formulas to, but it worked not for me. Simple example: \enableregime[utf] \setupoutput[pdf] \mainlanguage[de] \language[de] \setuppapersize[A4] \setupbodyfont[ss] \starttext Some text, we can read it without serifs. But the formula: $ \frac{1}{x-2} $ is not in the same font. \stoptext BTW is there another way to have units like g/(cm^3) as to set them as tex-formula. I dont no if the module units do such things. Thanks, Kai