The short answer is yes, you can backup the Netapp over NDMP to a NetBackup Appliance. This is a supported configuration. The following link covers how to setup Remote NDMP backup to disk, that is the same configuration as NDMP back to an Appliance.
http://www.symantec.com/business/support/index?page=content&id=HOWTO53137&actp=search&viewlocale=en_US&searchid=1315583678938
Please note that only Media Server side dedupe is supported with Remote NDMP backup.
On a side note version 2.0 for the 5200 code should be out very soon and it offer a number of improvements.
Other helpful links.
http://www.symantec.com/business/support/index?page=content&id=TECH76495&key=15145
http://www.symantec.com/business/support/index?page=answerlink&url=http%3A%2F%2Fwww.symantec.com%2Fbusiness%2Fsupport%2Fresources%2Fsites%2FBUSINESS%2Fcontent%2Fstaging%2FTECHNICAL_SOLUTION%2F31000%2FTECH31885%2Fen_US%2F3.0%2F267773.pdf&answerid=16777219&searchid=1315583489399
Paul Cummings
Senior Regional Product Manager
Information Management Group
Symantec Corporation