[SyncEvolution] sqlite backend

Hello, to add the sqlite backend for calendar can i just add us for contact these two files (SQLiteCalendarSourceRegister.cpp and SQLiteCalendarSource.cpp ) ? did syncevolution automatically accept this backend extention or there is a procedure to follow ? I remark that when setting syncevolution to synchronize using vcalendar1.0 the recur field is not synced it's totally ignored ,the other field are synchronized without a problem, should i activate something ? THX.