Volume control for 'headphones'

I have an AudioEngine paired to a Vault 2i but the only way I could get it to work was by 'pretending' it was a pair of earphones. Consequently, the volume control on the app doesn't work because the assumption has been made that earphones have their own volume control. This means the volume on any particular track is essential random and controlling it via the volume coontrol on the AudioEngine is inconvenient (to say the least!)

Any chance of including a volume control on the app for devices that need to be paired as earphones?