In the early 20th century, both the Serbs and the Croats of Bosnia claimed the Muslims as part of their ethnic group--eventually the Tito regime created a new ethnic category for the Bosnian Muslims. In earlier times when the peasants were illiterate and nationalism had not spread to that area, a lot of Bosnians may not have identified themselves as Serbs or Croats but only by religion.
I knew that in his last 30 years Andric did not identify with the Bosnian Croats but had not heard that he called himself a Serb...there were a lot of people in Yugoslavia who avoided picking an ethnic group and just called themselves "Yugoslavs."
Rest assured that Vatican knows ethnicity of people it is dealing with. And usual way Pope was dealing with Bosnians for more then millennium was crusade:
http://www.geocities.com/Athens/Troy/9892/bhhisto.html
Historically Bosnian Croats and Muslim are Serbs. They know their ancestors yield, converted and accepted religion of their oppressors - Islam and Roman-Catholicism. Thats big part of why so many of them hate those who did not capitulate and stayed Orthodox so much. Their origin is Serbian - they are just not ready to accept that.
I am fine with that and I accept their decision. At same time I recognize the truth, the same truth that best of Croats and Muslim were aware of. Take for example Mehmed Selimovic one of the greatest 20th century novelists of Southeastern Europe.
I descend from a Muslim family, from Bosnia, and by nationality I am a Serb. I belong to Serbian literature, while the literature of Bosnia, to which I also belong, I consider only as my geographic literature center, and not a distinct literature of Serbo-Croatian language... I belong, so, to the same nation and literature of Vuk, Matavulj, Stevan Sremac, Borisav Stankovic, Petar Kocic, Ivo Andric, and my deepest kinship with them I don't need to prove
http://www.answers.com/topic/mesa-selimovic
Who the heck I am to correct one Selimovic, or Andric?
Some historic facts on Serb Land of Bosnia
http://members.tripod.com/cafehome/serbdom-eng.htm
http://www.srpska-mreza.com/History/pre-wwOne/Bosnian-Serbs.html