Just to add that if you use the a77 popup flash as a wireless controller, it will be fine for the first 15 shots but then the flash hangs and can only then trigger once every 10 seconds or so. When the camera goes into powersave briefly , the hang is removed and you can carry on. Hopefully this is a software bug that can be remedied.
Using the f58 as the controller, mounted on the a77 there is no such problem.
Cheers