I've had a reply from Dooya and lots of product information sent to me (No prices) which I have not read as yet. However they did not answer my question about using the NWD Z-wave motor with the Dooya curtain track ?
Even if you were able to replace the motor with the NWD Z-wave one you would then lose the ability to use the Dooya Zig-bee wall controller and hand held remote control and you would only be able to control the curtain motor via Z-wave and Vera.
"From your inquiry mail., Z-wave is old network protocol, and we are using Zig-bee network protocol which is new protocol. It is more powerful than old one. I am sure you know this ^^ I don't think Z-wave and Zig-bee system are compatible, because they are different protocol.
For the curtain motor, attached is our curtain motor introduction. You may take for reference. Pls kindly let us know if you are interested in AC or DC motors. I think you can tell us more of your requirement."
I have several motor product documents to look through that they sent to me.
So they are using Zig-bee in their standard motors and remote controllers etc. Ideally we would want a curtain motor with both Z-wave and Zig-Bee so you could use the Dooya remote / wall controllers and also control it via the Vera Home Automation box.
Attached is the first image out of several: