Gary,
The GUI (5.6) still does not let you put -1 in the field length for HL/7 variant so I suspect 5.5 won’t either.
You will need to use a text editor to edit the field in the fields file in the appropriate formats directory. In order to get an entry you can c hange, you might go into the gui and change the OBX-5 filed length to something other than its current value (but not -1). Then go into the fields fiel with the editor and change the length to -1.
email: jim.kosloskey@jim-kosloskey.com 29+ years Cloverleaf, 59 years IT - old fart.