Add send as permission to a mailbox

You can use the following PowerShell script to added send as permission to a mailbox. It suppose to work on office 365, However I have experience some difficulty and following this up with MS support engineer.

Add-RecipientPermission "support" -AccessRights SendAs -Trustee "Bob"

Referance URL: http://help.outlook.com/en-us/140/ff852815.aspx

After talking to MS, it turns out the effect is not immidiated. After about an hours it start working.