Microsoft Activesync corrupts data

For half a year I am using now a smartphone powered by Windows Mobile 2003 SE, which gets synchronized using Microsoft Activesync with the computer at my office as well as the computer at home. The appointments and the contacts get synchronized. Unfortunately in addition I am using an old PocketPC and want to synchronize it as well. But Activesync seems to be unable for this scenario.

Activesync is synchronizing with each of the two devices without any problem. Sometimes contacts or appointments get duplicated. Not all of them, just some. It is quite annoying if you have contacts identically 3 or 4 times in your list. It gets disastrous, when you change a contact. Then you have after synchronization the old and the new contact beside each other. Changing a telphone number of a contact means you get illegal phone numbers on your smartphone. This is fatal on a mobile phone.

I talked to several people with the same problem, but a solutions seems not to exist (not in the knowledge base, not in the Microsoft forums, not by the support). Since Microsoft designed the platform that you have to use their Activesync, this means it is not possible to use both devices anymore. :-(

PS: Most of the build-in applications on the Windows Mobile platform are of poor quality, but normally there are a lot of good applications available for replacement. Not so for Activesync.