[Plugin: WordPress MU Domain Mapping] Filter Permalink

I use this function to retrieve a post from another blog of my network

<?php echo get_blog_permalink($ff_blog_id, $sub_posts[0]->ID); ?>

However, this function returns the original domain and not mapped.

Is there any way or filter that I can use?

http://wordpress.org/extend/plugins/wordpress-mu-domain-mapping/