Obs30 When I say "does not work" it means that the ASIAIR says "Connection failed". So there is not even a connection building up.
By watching how the ASIAIR communicates with my mount simulator, I could see that what it does is to initially send some innocuous command to the mount, which often is a "get mount firmware version number" command, and wait for a response, to validate that a correct mount is connected.
If ASIAIR does not get a response, or the response is some gibberish, it then goes into the catch all "Connection Failed" message.
You can also use a (USB) serial protocol analyzer to watch the messages; I had written one a long time ago:
(Some idiot actually pirated it, and placed the app (using the same name and app icon, no less) on the Mac App Store without my permission and with zero attribution to me, so I took revenge by adding newer features to Serial Tools -- like the NMEA parser :-) ).
You can also monitor the exchanges with a more recent WireShark, which will also watch USB traffic, and not just Ethernet traffic. Just a pain to filter away the zillion of messages.
Once you find the Avalon response to that handshake, you might be able to ask ZWO to accept that initial handshake from the Avalon's LX200 simulator as valid.
The ultimate solution for you might be to implement an "Avalon Proxy" (using an ARM chip, and even just using CircuitPython from Adafruit) that can translate a protocol the Avalon understands, into say the iOptron protocol. You can then use anything, including ASIAIR, that groks the iOptron protocol.
Heck, if you are really, really lazy, just pass all the LX-200 commands between ASIAIR and the Avalon's LX-200 simulator, except for that initial handshake that ASIAIR does not recognize.
For what its worth, the iOptron protocol is also a bloody mess too --tiny changes here and there for each of their new mounts. But at least it has a two-argument command to "slew mount at Nx sidereal rate for M millisecond"that gives very precise guide pulse instead of software timing it in a client like the ASIAIR. (Not that ASAIIR will implement that more precise command -- ZWO caters to the least common denomintor, including mount protocols.)