99% of ViaTalk's international rates are very competitive, but there are a few exceptions, such as Austria and St. Petersburg, Russia.  The second port of the Linksys PAP2 adapter allows to work around that.  Here is how:
- sign up for a no-frills account at asterisk2pstn.com
- get the admin credentials for the PAP2 from ViaTalk customer support
- enter the local IP address of the PAP2 adapter into your browser
- log in as admin
- select line2
- enter the asterisk2pstn credentials in proxy, password, display name, and user id
- under provisioning, select provisioning=no, in order to avoid overwriting these settings with the next power cycle.  This means you are now responsible for getting updates from ViaTalk when necessary, which is not a big deal though, since all that needs to be done is setting provisioning to yes again, saving, power cycling the adapter, and repeating the procedure on this page, which should only take two minutes.
- connect another handset to the second line of the PAP2 adapter
- save the settings
- power cycle the adapter

You're good to go and can make low cost calls to the international destination of your choice at a low cost.