MetaData SVG

Hello Everybody,

Fotolia (www.fotolia.com) will soon announce the launch of a vector 
bank. The specificity of this vector bank is that only SVG format will 
be accepted. We already accept images (JPG) and we use IPTC metadata to 
embed information within images (title, keywords etc). We are looking 
for the best way to do the same with SVG. Which data structure do you 
think will be the best for SVG format ?

Thanks a lot !

Thibaud