code:

---

$ADS_RIGHT_EXCH_MODIFY_USER_ATT = "0x02" 
$ADS_RIGHT_EXCH_MAIL_SEND_AS = "0x08" 
$ADS_RIGHT_EXCH_MAIL_RECEIVE_AS = "0x10" 
$ADS_ACETYPE_ACCESS_ALLOWED = "0x00"
$secobj = CreateObject("ADsSecurity")
$sd = getobjectoption("IADsSecurityDescriptor")
$dacl = getobjectoption("IADsAccessControlList")
$aceobj = CreateObject("AccessControlEntry")
$sd = $Secobj.GetSecurityDescriptor($mailbox.ADsPath)
$dacl = $sd.DiscretionaryAcl
$aceobj.Trustee(@DOMAIN+"\"+$strAlias).Put
$aceobj.AccessMask.Put($ADS_RIGHT_EXCH_MODIFY_USER_ATT)
$aceobj.AceType = $ADS_ACETYPE_ACCESS_ALLOWED
$dacl.AddAce.Put = $aceobj
$sd.DiscretionaryAcl = $dacl
$secobj.SetSecurityDescriptor($sd)  

---

But it doesn't give the result that i thought it should have. I thought that this would set the NT account with permissions on the mailbox but as you can see in the image that isn't working.