Iintegration of NetBackup,Isilon direct NDMP to a Datadomain as VTL

I seek references and information regarding integration of NetBackup,Isilon NDMP to a Datadomain as VTL andtapeout for long term.

THe suggested configuration is to backup an isilon with 100 TB of data (50 milion files ) via direct NDMP to a datadomain VTL.

tapeout weekly retention 3 month, quarterly 1 year, yearly retention 7 years.

On the Isilon, there will be a backup accelerator that is able to connect to the datadomain VTL.

I'll appreciate any input from any body with experience of this size and technology.