Yes it is possible with this workaround:
Start recording with an app, which supports 2 channel audio recording.
Then switch to the phone application and dial a number. After you pressed the green phone button, just press it again to cancel the call.
This procedure enables the camcorder mic for the phone noise canceling function. And HTC forgot to close it after a call, because another application still uses the audio engine
So return to your recording app via the double-click for the task manager and you will have 2 independent channel audio recording with left and right signal.
I found out this in August 2013 and reported this trick to 2 developers of audio recording apps, but they were not able to find out which command HTC uses to enable the camcorder mic. HTC did not answer a request to publish the method.
It is necessary to repeat this every time. If you pause the recording the camcorder channel will be closed and the device changes back to the mono recording via the main mic.
So I hope some developers of custom firmware could find a solution to enable the camcorder command via software command like enabling Bluetooth mic.