ActiveSync Guest Only Connection

I recently bought a Mitac Mio 268+ GPS device. This Windows CE 4.2 device works great as a PDA, but I still have problems with activesync.
Unlike several Win CE GPS devices, this unit has no built-in ActiveSync and uses a custom desktop communication application for basic tasks (MioTransfer).

I added the missing activesync files from Platform Builder 4.2 to my device:
cefobj.dll, eventstr.exe, rapisrv.exe, repllog.exe, rra_stm.dll and udp2tcp.exe.

When I connect my Mio device to my desktop PC with the USB cable, the AS connection is made very quickly, and I can explore my device through AS 3.8. The only trouble is that I get a "guest" connection only, and there is no option to create a partnership...
Has anyone a suggestion to force ActiveSync to create a partnership ? did I miss some steps (registry strings) ?

Edited by Geared2003 2007-02-21 7:34 AM

Registry is the first thing that came to mind. You should have keys for Windows CE Services beneath both HKLM and HKLM\Software\Microsoft. All the sync modules are registered under HKLM and the partnership store is under HKLM\Software\Microsoft\.

You also want to ensure that the AS PC hasn't got the 'guest only' flag enabled.