I have Evault 10 with exchange 2007 CCR.
I am not able to open archive attachment from OWA. In outlook it works fine.
Here is a troubleshooting guide for owa.
Couple of questions.
Are you able to see the Archive Explorer and Search Vaults tabs in OWA?
Are archived items showing the EV icon types?
Is anything else needed on this issue?
I just only installed Enterprise Vault, do you check connection form client ?
So, is this related to the original question?