We have a number of users working for and located at an external company. They access the local network via a VPN and have local AD accounts with corresponding exchange accounts.
I want them to be able to use their local email addresses and access shared folders on the exchange server however, they log into their primary domain first and access their own exchange server via outlook. I understand this means they cannot access a second exchange server.
The options as I understand them are so:
1. Outlook web access. Unfortunately this is locked down to a subset of privileged users with secure token ids.
2. Use a different client via IMAP. This is currently not available so I would have to fight with the exchange admins to get this enabled.
3. Run a virtual machine with a separate copy of outlook. Not really that nice.
Any other options available to me?