As you can see, to control soloing an object I have to write the following: "/ext/solo/src/1 1"
Create a button in Toggle mode and in the OSC - Address section locate that code. I don't get any results. I also tried to remove the "1" that follows after the space and set it in the Value parameters but without success.
Setting address to /ext/solo/src/1, on to 1, off to 1, and typeTags to i should do (Format "i" in your documentation indicates an integer is expected as opposed to the usual default number format "f" , for "float").