While I'm not sure I even understand the problem correctly, if you want to change the colors of an SVG image you can either use a package like Inkscape and it's XML editor or use a text editor on the svg file. As an example this is part of a pcb svg file edited with vi under cygwin (although notepad should also do):
circle cx="3.6" r="2.88" fill="none" stroke="#FFFFFF" stroke-width="0.72" cy="68.4"for your task the stroke="#FFFFFF" and specifically the #FFFFFF (which is white) is of interest. To
change that to black change it to #000000 (and visa versa to go from black to white).
The copper pads are a golden color (the above being the silkscreen layer):
circle cx="43.2" r="2.052" fill="none" gorn="0.1.0.0" stroke="#F7BD13" id="connector14pad" stroke-width="1.224" cy="3.6"/>
their color being #F7BD13 which you could change to black or white if you wanted.
Peter Van Epp