Hello Tremolounge,
I believe the best way would be to contact InsiderSoft support.
Font Agent Pro 4.0.3 has added support for QuarkXPress 8 according to independent websites, but the same is not stated on the InsiderSoft website.
Support Information:
http://www.insidersoftware.com/IC_contact.php
Please let me know if you have any further questions regarding QuarkXPress.