When the first Windows Mobile 5 devices started to hit the market, some of my customers tested Data Port Wizard on them and found out that it would not work. There is a documented workaround on MSDN but one of my customers found a better way by setting a single registry value. As a matter of fact, setting HKLM\Security\Policies\Policies\00001001 to 1 will enable all RAPI activities on the device.
Setting this registry key corresponds to the following provisioning script:
<parm name="4097" value="1">
Read all about this at its original source.