Missing Synch, Palm TX and Powerbook G4 running OS 10.3.9

I received a Palm TX for the holidays and I am frustrated with the inability to sync appropriately using iSync (I am a .Mac user). I read a review about the Missing Sync and I am very willing to purchase this program - however the article I read indicates that the program works best with OS 10.4 and that with previous versions of OS X the Missing Sync still relies on the iSynch Palm Conduit. Does anyone know what this means from a practical perspective? Is the Missing Sync not worth it if I don't update my Operating System (which I am disinclined to do)?
Thank you!
Ismee

Powerbook G4 Mac OS X (10.3.9)