AVAudioPlayer don't work in AVAudioSessionCategoryAmbient mode in iOS 6.0.1? - avaudioplayer

Question

In my app, I use a MPMusicPlayerController play .mp3 as background music,
and an AVAudioPlayer play sound-effect, just like button press, and so on.
The code is like this:
// Initialization code here.
AudioSessionInitialize(NULL, NULL, NULL, NULL);
AVAudioSession *session =[AVAudioSession sharedInstance];
//The background music and the sound-effect can play simultaneously
[session setCategory: AVAudioSessionCategoryAmbient error:nil];
[session setActive: YES error: nil];
m_sharedPlayer = [[MPMusicPlayerController applicationMusicPlayer] retain];
[m_sharedPlayer setShuffleMode: MPMusicShuffleModeSongs];
[m_sharedPlayer setRepeatMode: MPMusicRepeatModeAll];
[m_sharedPlayer setVolume:0.2];
// choose the first song
[m_sharedPlayer setQueueWithQuery: [MPMediaQuery songsQuery]];
[m_sharedPlayer play];
...
//when need play sound-effect, soundfilename is a NSString
NSData *data =[NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:soundfilename ofType:nil]];
AVAudioPlayer *audioplayer = [[AVAudioPlayer alloc] initWithData:data error:nil];
audioplayer =1.0;
audioplayer.delegate =self;
[audioplayer prepareToPlay];
[audioplayer play];
...
audioplayer is release after it has finished play.
The code is work in iOS 5.0. But in iOS 6.0, everything changed.
AVAudioPlayer don't play sound anyway.
If I change this line:
[session setCategory: AVAudioSessionCategoryAmbient error:nil];
To:
[session setCategory: AVAudioSessionCategoryPlayback error: nil];
The AVAudioPlayer will play sound, but it will break the play session of MPMusicPlayerController...
How can I find a way to play AVAudioPlayer but without break the background music? Thanks a lot for your help.

Answer 1

OK. I find the solution finally. In iOS 6.0, apple provide a new function call setCategory:withOptions:. It work.
So the code is just like this:
AVAudioSession *session =[AVAudioSession sharedInstance];
float version = [[[UIDevice currentDevice] systemVersion] floatValue];
if (version <6.0) {
[session setCategory:AVAudioSessionCategoryAmbient error:nil];
}
else {
[session setCategory: AVAudioSessionCategoryPlayback withOptions:AVAudioSessionCategoryOptionMixWithOthers error: nil];
}
Thanks.