Hmmm...haven't tried this with Maschine (no reason to in my workflow) but I'm not really understanding this; when using multi-timbral instruments like Kontakt and setting up multiple channels in live, each using an "external instrument" to grab a channel from kontakt, I'm able to send separate midi channel info (one channel per instrument in kontakt) and nothing gets 'merged into one' as you say. So why would it be any different with maschine? the External Instrument (in the Live device browser under instruments) is setup such that you have a "midi to" window, from which you select the multi-timbral VST plugin, and then beneath that it shows every available Midi channel, and you select the appropriate one for that track.
seems interesting, I didn't try with the external instrument device.
But reading your quote, it seems you SEND midi to multiple midi channels in kontakt, but the problem is when you want to RECEIVE multiple midi channels from the VST into live...??? external instrument is designed to be able to SEND midi and receive AUDIO on the same ableton track...
anyway, I just realise this 1) problem is the minor problem in my question, because even if live was able to receive separate midi channels from VSTs, fact is that maschine is still unable to send PCs and CCs to hardware or software synths...
The method I describe in my thread allows you to trigger ableton midi clips (including PCs and CCs) from the maschine, using maschine patterns notes to trigger ableton scenes via IAC driver, so as you seem to trigger EVERYTHING from the maschine, while the synths are sequenced by ableton mici clips... But there are still some limitations.
anyway, thanks for your help trial!