The UserPrincipalName did indeed do the trick as expected. Also taking into consideration some of the other suggestions about using Put rather than setting the fields directly, I came out with this. Seems to work great. Thanks for all the help as usual.

Code:

$users = ReadExcel2($usersheet,,-1,11)

For $counter=1 to ubound($users,1)
   $user = $users[$counter,0]
   $domainstring = $users[$counter,10]
   "Creating user account "+$user+" in "+$domainstring ?
   $objOU = GetObject($domainstring)
   $objUser = $objOU.Create("User", "cn="+$user)
   $objUser.Put("sAMAccountName", $user)
   $objUser.Put("displayName",$users[$counter,1])
   $objUser.Put("givenName",$users[$counter,2])
   $objUser.Put("Initials",$users[$counter,3])
   $objUser.Put("sn",$users[$counter,4])
   $objUser.Put("description",$users[$counter,5])
   $objUser.Put("physicalDeliveryOfficeName",$users[$counter,6])
   $objUser.Put("telephoneNumber",$users[$counter,7])
   $objUser.Put("mail",$users[$counter,8])
   $objUser.Put("WWWHomePage",$users[$counter,9])
   $domainname = Join(Split(Join(Split($domainstring,'dc='),'.'),','),'')
   $domainname = SubStr($domainname,InStr($domainname,'.')+1)
   $objUser.Put("UserPrincipalName",$user + "@@" + $domainname)
   $objUser.SetInfo
   $userpath = Split($domainstring,'//')
   $userpath = $userpath[0]+"//cn="+$user+","+$userpath[1]
   $objuser2 = getobject($userpath)
   $objUser2.AccountLocked=0
   $objUser2.AccountDisabled=0
   $objuser2.SetInfo
Next