First of all: Duplex rocks! Especially that you can use the devices “virtually”.
I planned to get me a BCR-2000 and with DUPLEX i can try before i buy… 
But here’s my question to that:
Is it possible to record your excessive knob-twiddling (e.g. filter manipulation) to the automation envelope? If so, how?
Maybe i’m just to stupid to find it…
Wow, didn’t even know you could “virtually” use the devices.
dont wanna play clever,but i dont think thats possible yet,someone please correct me if im wrong though.
Yeah, of course it makes sense to record your movements to the automation. At the moment, nothing get’s recorded to automation but it’s something we have been discussing, to get the best possible solution - that is, the best solution not just for Duplex, but for the Renoise API in general.
Personally, I would like to be able to raise a global flag in the Renoise API, “record_automation” or something. Then, when an automatable parameter is modified, it is automatically recorded as automation data.
This way, as a scripter, you don’t have to modify your code in order to make it output/record automation, it’s all taken care of behind-the-scenes.
My idea would be to set the parameter to be recorded manually. I’m thinking of that little box behind the parameter (at least in the native fx) where you set automation or jump to the corresponding envelope (i guess you know which one…). There you could set it to “record mode”, so no matter how or by what the parameter is changed, it get’s recorded…
{Off-Topic on}
Yeah, no one reads the “readme.txt” these days… shame on you… 
Quote:
" To make this easier, Renoise offers a bundled tool called Duplex, which
comes shipped with mapping templates for a bunch of common MIDI controllers.
Duplex also offers virtual UIs for configuring the controllers it supports.
This way you can virtually test out such controllers without having
to own them!"
{Off-topic off}
Another question: Is it impossible to record to automation at all? I mean, generally, even without using duplex, just with the renoise midi map? Or can a midi mapped parameter be somehow recorded?
Press CTRL+M, select parameter in DSP chain, move desired controller. Go to edit mode and move controller - viola!