There are several methods in the JDBC API specification that the DataDirect FMP driver does not implement…one of those is getPrimaryKey(), which happens to be critical for Servoy. There is no way around that…that I have seen. You can however use their JDBC driver with the RawSQL plugin…but Forms cannot be based off of FMP tables with that driver.
If you have FileMaker advanced, I suggest you check out my driver at http://goldcougar83.googlepages.com/home2 which uses XML and specifies a the primary key as part of the URL.
FYI, here was a comparison I showed at servoy world.