I've connected my PC running Cubase SX2 with my MIDI controller keyboard - Evolution MK449C through USB. The MIDI out from the keyboard is connected to the MIDI in of an AKAI MPC2000. I've programmed some buttons on the keyboard to MMC transport controls. The Akai is receiving and responding. Cubase is showing MIDI input on the meters when the buttons are pressed, but the transport is not responding. The ins and outs in the settings are set to the correct sources. What could be wrong? Is it that i can't send MMC on USB and that i have to send it through a MIDI cable?