As per a personal  communication from Waltraut Ritter, Organising Committee member,
WikSym+OpenSym 2013 Call for papers  is now open, Due date: March 17,2013

The conference has a special track for community contributions as well which can be made use of by researchers who are interested in sharing their findings but would like to publish subsequently in other journals.
As the event is scheduled together with wikimania, it is great opportunity for people to attend both.

Cheers
Arjuna