Sorry to necro this post but I am desperate to get some sort of answer.
I am having the same problem where I can't get get the AIRIO to manually set radio frequencies.
I have tried every single suggested solution in this thread, and the only thing that got it to work is to change my language to English UK. I thought that was the end of my woes but just about every command needs to be re-mapped because I don't have an English dialect and no amount of speech training is fixing that.
I thought that resetting the LUA code would fix the problem to no avail. This is what my voiceattack looks like when I try to say "radio tune 1 2 5 decimal 0"
Everything else works flawlessly, and was installed precisely according to the manual. Even the TACAN and Link commands work, but this is the only thing that will absolutely not work (Unless if I change text to speech language, but I really do not have time to re-map 919 keywords).
If anyone could help, I would greatly appreciate it
Edit: Here's my profile as well so you know I have the Airio extension added correctly