Do you happen to know which model of the FAS and StoreVault unit your customer is using for the replication from FAS to StoreVault? I'm attempting to replicate from a FAS270c to a StoreVault S500 without much luck. Attempting to initialize the replication gives a permission error. I'd appreciate if you can provide more insight into getting a FAS unit to replicate to a StoreVault unit.
I believe they're doing it from a 3020 (188.8.131.52) to the S550 (latest release).
A semi-related note is...I actually did a SnapMirror temporary setup to help a customer migrate data off an S550 over to a 2050 -- just a combination of doing the settings you see under "options snapmirror" (check the SnapMirror setup docs) and the settings in FilerView....was kind of messy but we got it working just enough for the data migration (afraid I didn't take precise notes as we were mainly just trying to get it working and the S550 was being wiped and repurposed after that).