When you have more than one email for each user in your exchange 2010, it's necessary to configure Exchange to support it.
How is steps necessary to do that:
**1) Create shared Mailbox.**
The simpliest way is use Exchange management shell(EMS) and execute following command:
**2) Assign permissions**
As next thing you have to assign permissions for users which will use this mailbox for sending emails.
Add-ADPermission "[email protected]" -User "UserWhoWillUseThisAccount" -Extendedrights "Send As"
**3) Use it**
Check "From" button in "Options" tab and enter shared address to "From" field in the mail header.
When mails will be forwarded back with error about "not enought permissions", simply remove exchange account from outlook and add it back again. This solution resolve my problem after 6 hours of debugging ;-(
**Usefull web links:**