iSync v3.0.2 can't find installed Palm Desktop v4.2.1 rev. D?

Hello.

I have the latest updates for Mac OS X 10.5.8 on a 3.5 years old 15" MacBook Pro. I also installed Palm Desktop v4.2.1 rev. D on it and it worked (saw all the data in its Palm Desktop). I am trying to get Apple's iSync to work with this old Palm Treo 680 device, but it doesn't see the installed Palm softwares: http://i.imgur.com/ovy8d.png ... What's wrong?

Thank you in advance. 🙂