Backup NAS Proxy by NDMP

Hi everyone.

I am trying to do the next:

I have a unity 300 in my main CPD that we will call it CPD1, then, I have other unity 300 in CPD2.

Unity from CPD2 has a NAS server where a department from the company stores their files there. This NAS is replicated against CPD1. I would like to do a backup from the repicated NAS in the destination (CPD1) using the NDMP protocol in order to backup it to a robotic library. 

 I created a NAS proxy in destination (CPD1) and enabled NDMP. I am using backup exec, and I am able to add the NDMP server, however, I am not able to list the NAS and I can't choose what filesever to backup.

Is it supported to backup from replication destination by NDMP? If yes, how can I do it?

edit: I tried to create an interface of Backup and DR test and enable NDMP in the replicated NAS destination directly. Then I add in backup exec the NDMP server using that new IP address interface but I get the same problem. 

Thanks in advance.