[NTG-context] Running Heads Question

Hi all, I have some trouble setting up the layout in ConTeXt: 1. I'm trying to place the running head in the margin, 5 cm away from the top. My original idea is to use \setupheader[margin][...], but it turned out that this doesn't work at all - the header is not in the margin, and the setups in the second brackets are simply ignored. 2. I'm trying to use oldstyle for section numbers, so i specified numberstyle=\os, but the dot in the section number become a right-oriented triangle. 3. In LaTeX, I can use \thechapter to obtain the chapter number when defining something. So what's the equivalance in ConTeXt? Any input will be appreciated! Thanks!! Sincerely, Helin