I would really appreciate if Orage was able to import Recurrence Rules from vCalendar files as specified in http://www.imc.org/pdi/vcal-10.txt
Orage relies on libical implementation. Better place for this enhancement would be in libical: http://sourceforge.net/projects/freeassociation/ Sorry, but Orage will not enhance to import this kind of RRULE unless somebody provides a patch to convert it to libical RRULE. It means a lot of (too much) work.