Comment 27 for bug 441195

I think I found the problem and the solution. The "Master" and "PCM" are not interchanged they are right, the problem is that pulse's path for "Analog Stereo" assumes that the LFE is between PCM and Master, and this is not the case.
For this kind of setups there is a path called "Analog Stereo LFE on Mono". There is a comment at the beginning of the file that says

; Intended for usage in laptops that have a seperate LFE speaker
; connected to the Master mono connector

But pulseaudio's debug information said this won't be enabled because the Element "Master Mono" wasn't available. I edited the file and renamed Master Mono to LFE and move it before Element Master and now it is working as a charm.
Now pulse set PCM to max and the raises Master and LFE together.

I attach my analog-output-lfe-on-mono.