powershell script to enable Unified Messaging

Hi all,

I am trying to automate the process of enabling mailboxes for UM.  I have the following line but it doesn't work.

Basically, I have a csv file with the following headings:
uname extensions mailboxpolicy secondarydialplan

The script should import the csv file, Enable UM and add secondary dialplan:

HEre's the script

$users=import-csv ".\umusers.csv"

foreach ($user in $users)
      {get-mailbox -identity $_.uname

      enable-UMMailbox -identity $_.uname -umMailboxpolicy $_.mailboxpolicy -Extensions $_.extensions
      set-mailbox $_.uname -secondaryaddress $_.extensions -secondarydialplan $_.secondarydialplan
}

Any idea what I am doing wrong?

Thanks