How to add metadata for Creative Commons Licences?

How can I add Creative Common licence metadata to my pictures in Lightroom?

The copyright status has only options for "copyrighted" and "public domain".

I guess I could select "copyrighted" and then add some blurb under "copyright".

In this case, what should the blurb be, to be legally binding? Are there any presets?

I found an interesting plugin for this

http://regex.info/blog/lightroom-goodies/creative-commons

but before installing add on, I would like to know if lightroom already provides

(as it should!) options to this end

which makes easy also to add metadata on importing files.

Thanks for any help in sorting this out!