Set a variable first and then reference the variable for the field name so it might look like:
Set Variable [ $filename ; "Order#" & Invoices::OrderID" & ".pdf" ]
I'm not sure where you are storing the file so I will skip that portion unless you need it. But next, set the export to the path (also as variable) and $filename.
thank you guys, now i got it. I appreciate your help!!
Have been trying to do something similar but keep getting stuck with an error "could not be created on this disk."
Will upload a screen-shot of message and script.
Any help would be much appreciated.
PS - On a Mac