What is the security policy and lifecycle of your clients exported emails?

I can see that my exported emails are stored on your file servers and are always available (since 1 month from now).

Sure, i must be authentified to reach my exported files, but i'm worried about two things :

1) How many time the exported emails are stored on your servers ?

2) A third party can read my files if he can access the "hard disk" of the server (because the hard disk is not wiped before released, because the hard disk is crashed or because the third party is root ).. What do you think about a feature that encrypt emails exports before store them into your servers ?

I can't find anything about this on the security policy you provide .

Thanks !