This option is available in Pamela Professional and Business only.

These Pamela versions support recording microphone and speaker to separate left/right channels.

You may upgrade from Pamela Call Recorder to Pamela Professional if you require this feature. Pamela Pro is available as 30 day trial version. Make sure you uninstall Pamela Call Recorder when upgrading to Pamela Professional or Business (Read this FAQ article).

The option to select stereo recording can be found in the Pamela options under "Call recording" and then "Additional".

See screenshot of Pamela Professional option screen below.