Trust Files on Remote Computers running Auto-protect Question

This option implies that SEP11 is intelligently aware of AV products running on remote servers, to avoid duplicate scanning of data accessed on a share. 

Does the remote server have to also be running SEP11 for this to work, or can it be another product, such as AntiVirus for Network Attached Storage?  If so, is there a list of server AV products (and versions)supported by this option?

Thanks