当字符串包含åäö时，如何按字母顺序对字符串数组进行排序？

I'm building an app in xcode4.3/Objective-C and have come across a problem when trying to sort an NSMutableArray. I'll populate it with strings from a sqlite database. The problem occurs with the swedish characters å, ä and ö. I'm building an app in xcode4.3/Objective-C and