Translation:Il mio giornale
It isn't interchangeable. To say something is possessively yours in Italian it's basically like saying "the my/yours/ours/his/hers item." The possessive marker goes in the middle of the term. So saying "il giornale mio" would be like saying, "the newspaper, my." The organization is just like that. Don't take my word on it though! This is just my educated guess from getting this far..