Further information here: http://forums.oracle.com/forums/thread.jspa?threadID=2230797

Just in case the thread disappears, the primary comment is:
Thank you for your help Jonathan. Using setAll() worked very well. The reason i used a callback instead of setProperty was that sorting the tableview was considerably faster with callback. If i add 100 000 rows instead of 100 rows in my code the difference is really noticable. Running a profiler i could see that the get function in the property was causing this.