Thanks for the answer. I will try the new version, but in the meantime I have read the css 2 standard and realized that they have redefined a pixel to be an absolute unit of size. from http://www.w3.org/TR/CSS21/syndata..html#46;

I need an SVG editor to make minor changes to svg files generated by another program (gramps). The result will be displayed on the web as SVG. Inkscape seems to work well, except that the length unit in the output is always in units of pixels, even if I select cm as the unit in document properties. ...