the only solution I have found is using the mailContact method. This is a hassle because you then have two lists, AD users and then the new contacts. There is no need to export the Domino address book as all the users are already in AD and have the mail attribute set. So what I did is created a powershell script that reads AD and creates a new contact for each AD user. It will remove existing contacts before adding the new one to keep the list upto date. I am going to run this on a schedule. Its not the best way but it seems to be the only way to do this.
#
# list all email addresses in active directory and create mail contacts
#
# Created By Thomas Wheeler
# wheelert@wheelerwire.com
#
$WarningPreference = "SilentlyContinue"
$VerbosePreference = "SilentlyContinue"
add-pssnapin Microsoft.Exchange.Management.PowerShell.E2010
$strFilter = "(&(objectCategory=User) )"
$objDomain = New-Object System.DirectoryServices.DirectoryEntry
$objSearcher = New-Object System.DirectoryServices.DirectorySearcher
$objSearcher.SearchRoot = $objDomain
$objSearcher.PageSize = 1000
$objSearcher.Filter = $strFilter
$objSearcher.SearchScope = "Subtree"
$colProplist = "name", "mail"
foreach ($i in $colPropList){
$objSearcher.PropertiesToLoad.Add($i)
}
$colResults = $objSearcher.FindAll()
foreach ($objResult in $colResults){
$objItem = $objResult.Properties;
if($objItem.mail -ne $null ){
#Write-Host $objItem.name " (" $objItem.mail " )" $objItem.sAMAccountType
$name = $objItem.name | Out-String
$email = $objItem.mail | Out-String
Remove-MailContact -Identity $name.trim() -Confirm:$false
New-MailContact -Name:$name.trim() -ExternalEmailAddress $email.trim()
}
}