Symptoms
Send As permissions granted to users in forests trusted by the Microsoft Exchange Server forest are not visible in the Send As Permission Wizard in Exchange Management Console (EMC) 2010.
Cause
This is the current design in Exchange 2010.
Workaround
To view all accounts that have SendAs rights on a mailbox , you can use this powershell command instead :
Get-ADPermission <mailboxname> | where {($_.extendedrights -like "*send-as*") -or ($_.accessrights -like "*Generical*")} |fl *
For further information, please see Manage Send As Permissions for a Mailbox
Get-ADPermission <mailboxname> | where {($_.extendedrights -like "*send-as*") -or ($_.accessrights -like "*Generical*")} |fl *
For further information, please see Manage Send As Permissions for a Mailbox