processflow services/trigger questions

I have been spinning my wheels here for a while...

How do I find out which service(s) are calling a particular processflow? and what the associated Lawson form is where this is being initiated?

I have looked in menu.do and cannot seem to find out how a processflow is being "kicked off".  I would like to pull up the processflow and see what triggers/services are calling it. I would also like to know if it is possible to determine which field values have been changed on the form that initiated the processflow so I can do some field level logic and make decisions in the flow based on which fields have been changed.

Is it possible to define extra form level variables that will be available in the processflow or am I limited to the variables that are available in that particular service?

I am trying to do some troubleshooting and this information would help me along.  I am using the "classic" processflow, not LPA.  Any help would be greatly appreciated.

thanks