Remove audio from camera?

Is there a way to completely remove the audio recorded by the camera? I see that if I select the "soundtrack" tab I can then adjust the volume of audio tracks that I add, but I'm unable to change/delete the audio taken by the camera. I took a bunch of video at an autocross event with the camera mounted on the windshield, so the audio attached to the video is just screaming wind noise. I recorded separate audio with a dedicated microphone that I'd like to replace the horrible sounds picked up by the Virb360, but I'm not smart enough to delete the original audio. Help?