Do you migrate Enterprise Vault data to Amazon S3? I'm not sure how many people have ever done this, I've certainly not heard of anyone. I mean in someways it does make sense to have some of your Enterprise Vault data out in the cloud, and Amazon has a vast amount of storage in the S3 product.
However it looks like there is a problem currently with the glue between Enterprise Vault and Amazon, as described in this following technote:
Do you use Amazon S3 in this way?