pulse audio & jack

[Mac]

When I installed 12.04 UbStudio I was pleased to see pulse audio
played nice with jack. (i.e. when qjackctl starts pulse sinks/sources
show up by default).

Is there any documentation or overview of how this is accomplished?
I'd like to understand and possibly modify what shows up, etc.

Or, can anyone post some ideas on where to start? (I googled a bit
with little success.)

On a related note: if I run/start qjackctl things work fine. If I then
tell qjackctl to stop and choose yes/continue when it prompts about
clients still connected it can't connect when I attempt to start it
again. The message says it can't connect(or start) to the server.

I'm guessing there are stale processes that are not allowing the
restart, but, I'm not real sure where to begin to determine how to
correctly stop jack so it doesn't get it's knickers in twist.

Regards,
Mac