Are you running Apache in Worker mode or Prefork mode?
If you're not sure, run this command:
$ httpd -l
and check to see which setting you are using (you will see either "prefork.c" or "worker.c"). From my experiences, spyce doesn't behave itself well under Worker mode wrt sessions/pools (nor does php for that matter), so you'll want to switch to prefork mode.
If you're already running prefork mode, then you can ignore the above. I am using pool and session successfully w/ Apache 2 in Prefork mode using mod_python and have the following lines in my files:
If I recall correctly, Redhat (and related) distros install Apache in Worker mode by default.