If you have an API documentation for your device, you can compare it with the original Stream Deck API. If there are no differences in the Websocket messages, you can try your luck and download the bundled plugin from my GitHub project page (not the installer), extract it with 7-Zip into your Ulanzi directory and maybe you just have to edit the file "manifest.json".

In my Hotkey action, you enter any string (like "toggle-wind") into the field "SimHub Control". There is nothing to configure in the Hotkey action about long keypress, because SimHub has its own internal detection logic for this.

Then in SimHub you open the control assignment (to stay in my example: "ShakeIt Wind", tab "Controls", "Switch wind activation"). In the dropdown, you select "LongPress", then you press the button on the Stream Deck. SimHub should change the title in this dialog to "PropertyServerPlugin.toggle-wind".

Now if you "save" and switch to the tab "Wind profile", a short press on the Stream Deck key should not alter anything, a long press should move the large toggle slider "Disabled/Enabled" in SimHub.

unfortunately I can not make the long button press to work, maybe I miss something, but simhub only recognize the button assigned to the short button press, does not matter how long I press the button. Is there anything special? 

Unfortunately, there was a bug in the previous version: The ShakeIt browser did not display anything. Please download this new version.

* Same version as before

StreamDeck Plugin v1.13.68: https://github.com/pre-martin/StreamDeckSimHubPlugin/releases
* New installer for the StreamDeck plugin
* Support for custom flag images
* Flashing flags

The new “Flags” are certainly not a killer feature, but there have been significant enhancements to the internals of the plugin:
The plugin now has its own image processing - this is what made the section flags and flashing flags possible. And this makes new features possible, which I am already working on.

There is a video on YouTube on how to use the new installer: https://youtu.be/4Zh_6QLN8AA

Please read the documentation about the new "Flags" and the usage of custom images: https://github.com/pre-martin/StreamDeckSimHubPlugin/blob/v1.13.68/doc/flags/Flags.adoc

Not at the moment.

But I have just implemented a completely new image handling in my plugin: Up until now I used the Stream Deck software for the images, and my plugin was switching the state between "on" and "off". Now my plugin can take over the image handling and send whatever it wants to the Stream Deck, so I can display more images - e.g. a third one.

This first feature is already implemented and use by the new "Custom Flags" action, but not yet released. See https://github.com/pre-martin/StreamDeckSimHubPlugin/issues/123 for an example.

At the moment I am developing a feature that builds on the “Custom Flags” feature and allows custom flashing (“x” milliseconds on and “y” milliseconds off). When this second feature is ready, there will be a new release of my plugin.

After that, I will integrate these two features into the existing “Hotkey” action and allow a third state there. So it will still take a while...

The Problem was the missing and incorrect Configuration of the Buttons on StreamDeck, so maybe my mistake helps other Users.

So a simple Problem and so much Time, it was to easy to see...

I open a Ticket at Github with the files

And yes the Video is great, and looks so easy ;-)