I've been tasked with configuring Exchange Federated Services between two organizations utilizing the Microsoft Federation Gateway, lets call them Company1 and Company2. I've completed much reading including this: http://technet.microsoft.com/en-us/library/dd638083%28v=exchg.141%29.aspx#EA I understand I need to establish an Organization Relationship then setup a Sharing Policy and from what I'm reading the highest level of 'sharing' I can achieve is: Calendar sharing with free/busy information plus subject, location, and body, Contacts sharing (from article above) I have a stakeholder with a mail account at Company1 asking if they will be able to have 'Send As' permission for an account that exists at Company2 after Exchange Federation is in place. I cannot find any documentation that says this is actually possible and I assume I would need Active Directory Federated Services and a trust between the two domains to make that happen. Any advice would be greatly appreciated. Thank you.

Yes, this required active directory federated Services enabled, once established you can add the send as permission to the mailbox from other company, by changing the scope in management console to other company with proper exchange rights Calendar Sharing helps only to see free /busy info but not permisson for mailbox folders.

Yes, this required active directory federated Services enabled, once established you can add the send as permission to the mailbox from other company, by changing the scope in management console to other company with proper exchange rights Calendar Sharing helps only to see free /busy info but not permisson for mailbox folders.