In the meantime I managed to find an implementation reference on the DMPro manual and it reports aftertouch as NOT supported.
I still don't know if MD actually sends an aftertouch signal to implement the choking, but I'm prepared to the worst scenario.
For those interested, here is some info I gathered.
Warning: long blurb ahead! It seems the interweb has very few information about DMPro workings, despite it has been a best seller for a while, so I summed up what I discovered, should this be of help.
Choking on this module is an odd beast: is seems one and only one input supports choking the CY-8 cymbals (sorry for misposting above about two CY-6, they are actually CY-8... but I guess few differences in construction). Natively the module has a very convoluted way to mute the cymbals, using an additional input just to get the "choke" signal and playing a silent note, thus stopping all other sounds. There are actually more grim details involving Y-cables and the creation of "mute groups" at kit level, but I will spare them to you. Those interested can read about the topic in the "DM Pro Reference Manual" you can find here and there online (I can send a copy if needed).
Still that single input (and only that one) works out of the box with the CY-8 without all that fuss. I read something (here:
http://is.gd/i5IOUR) about a 2.0 firmware upgrade the DMPro undergo when Alesis launched the DMPro Kit with Hart pads. In that occasion, it seems (
http://is.gd/YMkZtl), one input had been rendered "chokable" to support the only kit crash. In fact the kit PDF manual I just found reports: "When you hit the cymbal and grab the edge, the cymbal sound stops abruptly. For advanced choke set up, please refer to the DM Pro Reference Manual."
This makes me think about sort of logical "hard-wiring" of the convoluted muting system on that single input marked as "cymbal". If you want more you have to sweat hard. Or (that's my sincere hope) maybe using a trigger-to-midi machine able to send a chokable signal via MIDI.
What "chokable cymbal via MIDI" means is the core issue and frankly it goes beyond my knowledge. I suspect there is nothing like a standard "choke signal" even if have memories of coding it somehow in Guitar Pro...
Anyway, nothing beats experience, so if I can manage to send the MD choke signal/sequence to the Alesis brain and hear what happens, I guess I can avoid wasting YOUR time reading my fuss. On the other hand, should this work, the combination DMPro + MD would be a killer, cheap and full-featured alternative to those relying on TD-10+/ DM10 and arrays of expensive TMC-6.