That supplement is already in the coded sources
wow that test character I rolled to make sure the spell was in the source was one of the best rolls I've ever done... 12 total mod.
Once in pcgen and with pathfinder loaded, without a character loaded go to Sources- Select sources- click on the advanced tab and enter the companion name -add selected, then I would save this selection and use this modified source material when using the character.
That should get you what you need.
Hope this makes sense.