Oh well...you would expect that "good" file formats are supported by all major applications. Right?
Surprise, surprise. Ever tried to export a plot as svg in Mathematica? Works perfectly...and the resulting svg is perfectly empty.
How do we get an svg in these cases? Probably, the least problematic way starts with the creation of an eps, i.e., an encapsulated postscript (without preview, please). Importing this eps file in scribus and exporting it as svg already constitutes the end of the least problematic way.
Alternatively, you may want to try the canonical way: pstoedit -f plot-svg infile.eps outfile.svg. Or eps2svg from Justus Piater. Or OpenOffice Draw, which does an acceptable job in many cases (but in other cases, it exports png images embedded in an xml file as svg :/).
For me, scribus worked flawlessly. The high-resolution plots obtained by clicking on the respective images below are, by the way, smaller than their own preview. Cool. ;)