Assuming that you stored the .pdf file on the IFS (using OVRPRTF parameter TOSTMF),
this is how I have solved a similar task:
First of all make sure that PCO is active. Use STRPCO and MONMSG(IWS4010).
Then build a variable containing path and filename of the .pdf. Fx CGHVAR &STRING to ‘d:/[mypath]/[mydocname].pdf’ .
Assign a drive-letter to your path: NET USE [d]: \\[myi5]\[mypath] [mypassword]
Now run the STRPCCMD PCCMD(&string) PAUSE(*NO) and your .pdf file will be opened and displayed.