Inkscape, is an Open Source SVG-based drawing tool. It supports CC licensing within the application and also has a simple way to add metadata to SVG files from within the application.
Here is the code that is in Inkscape's SVN repository for making the License and Metadata Dialogs possible. Please use them as examples for coding your own metadata and license selectors:
Inkscape's gtkmm-based license chooser
Inkscape's gtkmm-based metadata chooser