I'll explain everything in the guide
The main reason for which custombuild doesn't get FastCGI working (even if it actives the builtin FastCGI handler, that's what you see in phpinfo() or `php-cgi -v') is that it's pretty hard to integrate in an existing solution.
It's been 6 months since I tried FastCGI the first time, since then I've had to read
a lot of very old
and WRONG documentations, tutorials and manuals to make it work just as
I think is the best way.
Furthermore, running FastCGI with a very special config is the only way to make a proper use of APC/XCache/eAccelerator (PHP opcode cachers) if you can't use mod_php because you use the "worker" MPM Apache2 connection handler and any PHP not-threading-safe module. If you are on mod_php/prefork, there is absolutely no need for FastCGI AFAIK.
Like I said, it's hard and I'll explain in the detail all of that.
I would love your help skaag, just added you on MSN. Let me know if you prefer AIM or Skype.