[SyncEvolution] Syncevolution on Nokia N900 : Force SyncML 1.1 ?

I'm trying to synch calendar data on Nokia N900 with my Desknow server (www.desknow.com) using Syncevolution 0.9.2-4. I receive the following error after triggering a synchronization : "SoupTransport Failure: http://servername/desknow/sync via libsoup: Internal Server Error". Log of the Desknow server : [http-1000-Processor23]SyncServer: Unexpected exception. org.syncml.SYNCMLParseException: Unexpected Token [namespace=syncml:devinf,name=CTCap,ext=-1,id=150,type=1,line/column=1/288] I already contacted Desknow's support and they are telling me "Syncevolution uses the Synthesis SyncML engine, which DeskNow is fully compatible with. Make sure it uses SyncML 1.1 protocol". So is there a way to force Syncevolution to us SyncML 1.1 ? Any help on how to solve this would very much appreciated, thanks. Christof