This sounds crazy but my brother in law is trying to do this, my sister in law received papers from him where he has filed for divorce from her, in the 1st Sharia court in Cotabato , he is an American and has converted to Islam, at least untill after the divorce, my sister in law is Catholic, I thought this will never work, but I found an article where the supreme Court of the Philippines has unanimously ruled in favor of a husband who divorced his Filipino wife a Catholic in Sharia District Court ,I am waiting to see how this works out