Homegrown Sounds has released Multitimbral Control, a simple free VST plugin for Windows that allows control of up to 16 MIDI channels and so is ideal for controlling a hardware multi-timbral sound module. It allows you to take control over Volume, Pan, Program Change (MSB, LSB and Program Number), plus 2 assignable MIDI Control Changes which are mapped to knobs for overriding a preset.
It's useful in hosts which don't have easy control over external devices and particularly when they don't have MSB and LSB options. Many hosts simply have bank/program number which is not enough for some hardware which need MSB and LSB to select banks, such as Emu Proteus synths. The other benefit is that you can control the entire sound module from one place rather than on the MIDI channel which makes mixing and tweaking much more intuitive.
If you understand mixing desks the plug-in should be intuitive enough, the main problem will be getting it to talk to your hardware if you are not familiar with how to set this up in your host. All hosts behave differently, but most will add the MIDI outputs of MC to the MIDI inputs list, and so you can then send the MIDI input to the correct MIDI port where your target hardware is attached. Generally this is the same as setting up a MIDI track to play the hardware, except instead of choosing your keyboard/controller as the input you would select the MC output instead.