Yep, I'm fighting with the same thing. If you are getting text created in Inkscape into fritzing (I can't even do that with Inkscape created text!) all you likely need to do is edit the svg file with a text editor and remove the px from the font-size (any of the font items I expect) so the number becomes 80 instead of 80px. The px confuses Fritzing and the parts editor changes the font size to 0 (with thanks to Steelgoose who found this for me!) once the parts editor edits the part. If that doesn't help, then its possible that Inkscape is using the trans function for text (which is the problem with Inkscape created text) which Fritzing doesn't support, for that the only solution I've found is to duplicate already existing text created by Fritzing and modify that, Inkscape doesn't seem to mess with the xml for that. Hope this helps!
Peter Van Epp