USB headset for phone call audio

Is there a way for SoundAbout to let me route the speaker and microphone through a USB headset specifically for phone calls?

On my phone the USB headset works perfectly with Skype and other VOIP applications (just plug and play, no special effort). But with regular phone calls, the phone completely ignores the USB headset, even though in the SoundAbout settings, USB Host Usage and USB Client Usage are both checked, and Let App Decide is checked for phone call audio.

Running CM12.1 on a OnePlus One and SoundAbout Beta Version 2.6.6.1

The Android Audio Policy Manager won't allow USB during a phone call.

When in a VOIP call the mPhoneState is set to MODE_IN_COMMUNICATION.
When in a real phone call the mPhoneState is set to MODE_IN_CALL.

The code below is from the Android Audio Policy Manager. It say if the phone state is NOT (!=) MODE_IN_CALL, then allow AUDIO_DEVICE_OUT_USB_ACCESSORY and AUDIO_DEVICE_OUT_USB_DEVICE.

You can also see that Dock output and Aux Digital (HDMI) is not allowed for phone calls.

if (mPhoneState != AudioSystem::MODE_IN_CALL) {
device = mAvailableOutputDevices & AUDIO_DEVICE_OUT_USB_ACCESSORY;
if (device) break;
device = mAvailableOutputDevices & AUDIO_DEVICE_OUT_USB_DEVICE;
if (device) break;
device = mAvailableOutputDevices & AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET;
if (device) break;
device = mAvailableOutputDevices & AUDIO_DEVICE_OUT_AUX_DIGITAL;
if (device) break;
device = mAvailableOutputDevices & AUDIO_DEVICE_OUT_ANLG_DOCK_HEADSET;
if (device) break;
}