Thank you Martin for your support.

I am afraid the Jigoshop team won’t handle this request.
To them, it is hard-coded in WordPress as the plugin relies on WP Custom Post Types. I quote this post from their forums : http://forum.jigoshop.com/discussions/questions/147-url-and-permalink-help

Since Jigoshop works with WP core Custom Post Types, I thought that maybe your plugin could do the job more easily by supporting these extra Custom Post Types.

I hope it make some sense !

Best regards,
Antoine