[NTG-context] pagenumbers in margin

Hello, After a long period of "Context inactivity", I am again into document preparation. I want to put the pagenumbers in a doublesided document in the outer margin. So far no problem at all... but I want the number to be placed in a 3cm wide grey box, wich I do with an inframed command within the pagenumbering setup. This also works more or less, but (see if I can explain this in plain english without using figures !!.....) : The grey box with the pagenumber aligns its inner border with the inner border of the outer margin. What I want is the grey box to align its outer border with the outer border of the outer margin..... Any suggestion ? Geert Dobbels.