Okay, I'm not at my Mac right now, but what's the name of the app that launches when you initiate a HotSync from your Palm? I know HotSync Manager isn't it (guess that'd be too obvious) -- I think it's Conduit Manager. Anyway, start a HotSync from the Palm and pay attention to which app it launches and where it's located.
Now launch that app on your Mac. I'm pretty sure that'll initiate a HotSync, too, using your normal connection settings. You could use AppleScript or the terminal or Startup Items to launch it.
Of course, if I'm wrong: boy do I feel dumb for not just waiting 'til I got to my Mac to post. But I'm pretty sure on this'un..
Good luck.