2-way NDMP over Unity CNA ports

Hello,

I have a customer with a Unity who wants to backup his fileservers on Unity using 2-way NDMP over SAN. Tape Drives are connected to two different fabrics. On Unity onboard CNA ports are installed with FibreChannel SFPs. Additional FibreChannel moduls are not installed. Customer does use sync replication on Unity. From Unity NDMP whitepaper I got information that NDMP 2way backup cannot performed over sync replication ports. Per default Unity spa_fc4, spb_fc4 are configured as replication ports. As we do not get NDMP connections to tape drives that are connected over fabric to these ports I guess that spa_fc4, spb_fc4 do not accept NDMP traffic even if sync replication is not configured. Is that right? If yes, is it possible somehow to disable sync replication feature so that these ports can be used for NDMP backup?

Thanks.

Robert