This is not recommended during the recording process with ML-2. The VMR modules that relate to the ML-2 namely VMC Classic Instruments and VPC, are expecting a flat, uncompressed signal. Imagine if you will trying to compress the signal before it had hit the preamp (or even the mic!). The recommended practice in this case would be to use the hardware compressor as a hardware insert after the VMR processing. You can then commit this to tape / disk by the usual methods.