Hey Giancarlo,
The Manuel doesn’t says it only gen-lock on 24 frames, the camera has three options in its gen-locking menu, the top one is for 24 frame shooting if you are not shooting on 24 then you can select the second option.
Which device is you using for gen-locking?
And stereobrain itself is a better and simple tool, there is a very rare chance to have any problems on it. First you want to check and make sure that your settings is perfect and if you have any doubt you can mail me directly.
-dhanil
dhanilcuts@gmail.com
Mumbai