The only FXG editor I\'ve seen for Flex is by 7jigen, works online or as a Flex app.
Does anyone know of a different one? It can be done in Illustrator I think, but
Firstly, RIAGrande's answer is correct. I followed his steps and they worked. Here is a little more information for future reference:
The Inkscape bug report for FXG with downloads available under Patches can be found at https://bugs.launchpad.net/inkscape/+bug/625140. These files (when uncompressed) should be copied to the location mentioned by RIAGrande
I made my little icon, but he exported FXG file was not indented, so used http://xmlindent.com/ to fomat the file, Downloaded, copied to my project in Flash Builder and renamed as .fxg file.
To use the FXG file, did the following:
For posterity, here is the icon and resulting Inkscape FXG code: