I was in the same boat a while back. VPN passwords would expire and the users would have to call the service desk to have to reset their passwords.
Unfortunately, I resolved this lack of notification using a PowerShell script.
All users now get a notice every day if their password is less than 9 day of expiration date.
The script is scheduled on a Domain Controller to run once a day.
(It would amaze you to learn how many users wait for the last day before changing their passwords, even with no VPN)
If this can be scheduled in Lansweeper, I'd might be interested. I do like the flexibility of the custom email message, text, etc in the PS script though.