With DDVE 3.0 it seems to be supported:
Supported Data Domain features
l Secure multitenancy (SMT) with Network Isolation Support in 6.0
DD VE does not support SMT.
When a DD VE instance is replicating data
to a Data Domain system with SMT, the
security mode of the destination
DD VE 3.0 supports Secure Multi-tenancy (SMT) and was made Generally Available (GA) on Sept 19th. You can also use DDMC 1.4.5 to manage SMT on DD VE 3.0.
I'm curious to know if you've tried configuring and if you are running into any issues that we can help with?