SamyGO

I think I can make such a thing. But, I needed a WMN5290A & A series television for reverse engineering.
After reverse engineering signals that captured from exlink, I can place a utility that emulates A series exlink commands.
So it's highly possible to do such a thing. But unfortunately I don't have even dump wall mount.
If you donate me a one WMN5290A with A series TV, than I can implement it for free

You also reverse engineer this device to make compatible with B series.
But you needed those two devices too for capturing commands from exlink.

Okey.
Here is that what you need.

Does TV recognize wall mount attachment?

You needed to capture traffic from wallmount to TV.

Protocol is RS232, use special Ex-Link cable to connect TV to Wallmount and Computer same time.
After you needed to capture signals from remote controller.
When you got the exact strings that control wallmount, you can prepare a Game mode utility that prints those strings to /dev/ttyS0.

This is the way how to do.

It's ExLink cable, and you can use any terminal application on PC side.
Please look wiki pages for cable schematic. (Probably you can find it on B series wiki pages)