I want to run Ensemble FireWire at 176.4 or 192 kHz, but I only see 44.1-96 kHz in Audio MIDI Setup.

To operate Ensemble at a sample rate of 176.4 or 192 kHz, it’s necessary to set I/O Allocation to either 10x10 or 8x8. The I/O Allocation setting is found on the Settings tab of the Maestro Control window. As ADAT optical I/O is not supported at these sample rates, their associated Firewire paths are disabled to conserve bandwidth. After changing I/O Allocation, it’s strongly recommended to restart the computer and power cycle the Ensemble.