Enterprise Vault DWA client provides similar functionality to the Enterprise Vault extensions for Lotus Notes.

Note that, in order for users to be able to open archived signed or encrypted MIME items, there must be an SSL connection to the Enterprise Vault Domino Gateway.

If there is no such connection, users receive the following message:

Unable to complete the current operation.
SSL is required for secure mail,
but is not enabled on Domino Server.
Please notify your administrator.