I have owned a Crave for a while now, but only recenly starting delving into the patching options more. So here is a useful nugget about how to use the Modwheel on an external synth to control parameters on Crave.
Assign Ouput
There is an output port on the Crave called Assign. Connect the Crave via USB to a computer and use the synthtribe software to set Assign Value to MIDI CC#1
Now the Modwheel on an external synthesizer (which by default usually uses MIDI CC#1) connected via MIDI can control the Input parameter that you patch the Assign Ouput port to, such as VCF CutOff or VCF Res