PCML novice quiestions

Got the RNF0302 on my module compile, when compiled with PGMINFO(*PCML : *MODULE). The real objection appears to be:
"Error: return value must have type="int" and length="4". (E)."

Archives indicates that a return value is restricted to a 4-byte integer. IBM Knowledge Center for i 7.1 shows a number of data-types not supported for return/input parms (char is not one listed as excluded), and also has the following verbiage regarding output-only parms:

<snip> RPG does not have the concept of output-only parameters. Any parameters that do not have CONST or VALUE coded have a usage of "inputoutput". For inputoutput parameters, the ProgramCallDocument class requires the input values for the parameter to be set before the program can be called. If the parameter is truly an output parameter, you should edit the PCML to change "inputoutput" to "output". </snip>

Okay, fine. RPG (at 7.1 TR7) does not allow CONST or VALUE on the return parm (except VALUE for INT 4.0 only). So how might one edit the PCML if a module fails to compile? And just where does one find the PCML to edit?

Or better, how might one set up an acceptable return parm that permits a character string?

I am doing some proof-of-concept work for ultimately creating a web service with IWS to support an Electronic Bill Presentation & Payment application. I was able to create the web service for a procedure that didn't return any values, but as I expand toward real world work, I crash into this. Can't imagine being restricted to not being able to return anything but 4-byte integers.

How do real developers do this?

Many thanks,

Michael Koester
Programmer/Analyst

DataEast