How can I use cwenc with Sonar 4?
You cannot. Cakewalk changed the interface to the encoder completely for Sonar 4, so cwenc will not work with Sonar 4. And as I have absolutely no plans of buying Sonar 4, it is very unlikely to happen in the future. The good news is that Cakewalk has added an option to specifically configure an external encoder. I’m told that it is accessible in the “Tools” menu. You can then configure Sonar to use the Lame encoder directly, and you have thus no need for cwenc anymore.