As I know the difference between PTS and Java geodata is only in data structure. Of course you can find some free shared converters using Google, but 99% that this wont have any positive results. Also as if Geo Engine will recognize PTS Geodata. The same thing.
You could create geodata files from the C4 client... but you wont see much of a difference. The problem are not the geodata files ,its L2J's Geoengine.
This is one of last "areas" where L2Off servers are better when compared to L2Java.
DnR did a great job allready by implementing 2 geodata-engines to the project.
It was way worse before. (blame the lazy l2j devs)