I'd suggest the following experiment:
Set the VH-12 on its own stand, so that there is no physical crosstalk.
Set the hi-hat xtalk send to 0.
Now try hitting the hi-hat - see if any other pads light up.
If any other pads light up, then the signal from the VH-12 is too strong, causing electronic crosstalk inside the module. If this happens, the best solution would be to add a resistor to your own custom hi-hat cable - about 80 kOhm should do the trick.