[Plugin: WP-PostRatings] different rating images for different urls

I’ve got my WP installation spread across 2 urls and I’d like to display stars on url A and squares on url B.

Would I need to edit postratings-options.php and add in code to select an image used if url A vs B or would there be a better way of doing this?

Maybe in js?

http://wordpress.org/extend/plugins/wp-postratings/