Some genealogy software does not follow the gedcom 5.5 standard as closely as PAF 5.2 does, but PAF should allow you to include unsupported info in the notes. Give it a try. Create a new PAF file with a new name and import the gedcom. Ask PAF to include listing file in Notes. Then check the PAF data file to see whether the ASSO information appears in the individuals' notes.
If not, you may need to copy and paste from the gedcom file into PAF's notes the hard way. I hope not.