Hi Rob, i've been wondering how to do this too. I think it's not possible because as soon as you turn on the VS700R it's default settings for the direct-monitoring are not ouputting the Fantom channels. (Same as phantom-power is no longer on by default)
A Firmware update would possible be able to 'fix' this.......
** I am not very proficiant with SYSEX messages, but maybe the VS700R unit would respond to those. Maybe it's possible to change the direct-monitoring states through sysex.....?? **
Maybe some other users have experimented