Yes; I used command-line, x264vfw via VirtualDub, Simple x264 launcher, TX264; with several x264.exe for each, but nothing...
I just finished to encode it, and splikes are just a bit more than 41mbps; I will try another setting, then post results here.
Maybe tomorrow I'll find out some time (and courage) to format the main HD of the twin PC and install (again) the OS... keep fingers crossed!