Yamaha DTXpress/DTXplorer/DTXtreme

I currently use a DTXpress 3 Special set and I am considering upgrading 
to the DTXpress 4 module and keeping the rest of my kit. 
I currently use the HH65 Hi Hat pedal as an effects pedal, connected to 
input 1(kick drum input). The trigger setting needs amending to "HH65 
controller" and it then works fine.It is also referred to in the manual 
as how to use the HH65 as a double bass drum pedal. However, I have 
downloaded the DTXpress 4 manual and the only mention of this is on 
page 14 refering to the inputs 9,10,11&12 stating that a further bass 
drum pedal can be connected, to use as a double bass drum set up-but it 
doesn't actually mention the HH65. My question is, has anyone used a 
HH65 in any of these inputs on the DTXpress 4 and got it to trigger a 
voice etc. Thanks