diff --git a/src/AudioToolbox/AudioServices.cs b/src/AudioToolbox/AudioServices.cs
index 918e2a04ee..c50a4ebb3e 100644
--- a/src/AudioToolbox/AudioServices.cs
+++ b/src/AudioToolbox/AudioServices.cs
@@ -61,12 +61,12 @@ namespace AudioToolbox {
 		//static extern AudioServicesError AudioServicesGetProperty (AudioServicesPropertyKey propertyId, uint specifierSize, IntPtr specifier, out uint propertyDataSize, IntPtr propertyData);
 
 		[DllImport (Constants.AudioToolboxLibrary)]
-		public static extern AudioServicesError AudioServicesGetProperty (AudioServicesPropertyKey propertyId, uint specifierSize, ref uint specifier, out uint propertyDataSize, out uint propertyData);
+		public unsafe static extern AudioServicesError AudioServicesGetProperty (AudioServicesPropertyKey propertyId, uint specifierSize, uint* specifier, uint* propertyDataSize, uint* propertyData);
 
 		//[DllImport (Constants.AudioToolboxLibrary)]
 		//static extern AudioServicesError AudioServicesSetProperty (AudioServicesPropertyKey propertyId, uint specifierSize, IntPtr specifier, uint propertyDataSize, IntPtr propertyData);
 
 		[DllImport (Constants.AudioToolboxLibrary)]
-		public static extern AudioServicesError AudioServicesSetProperty (AudioServicesPropertyKey propertyId, uint specifierSize, ref uint specifier, uint propertyDataSize, ref uint propertyData);
+		public unsafe static extern AudioServicesError AudioServicesSetProperty (AudioServicesPropertyKey propertyId, uint specifierSize, uint* specifier, uint propertyDataSize, uint* propertyData);
 	}
 }
diff --git a/src/AudioToolbox/SystemSound.cs b/src/AudioToolbox/SystemSound.cs
index 23fbca9a36..70295f4cb8 100644
--- a/src/AudioToolbox/SystemSound.cs
+++ b/src/AudioToolbox/SystemSound.cs
@@ -101,8 +101,12 @@ namespace AudioToolbox {
 			get {
 				uint out_size = sizeof (uint);
 				uint data;
+				AudioServicesError res;
+				var soundId = this.soundId;
 
-				var res = AudioServices.AudioServicesGetProperty (AudioServicesPropertyKey.IsUISound, sizeof (AudioServicesPropertyKey), ref soundId, out out_size, out data);
+				unsafe {
+					res = AudioServices.AudioServicesGetProperty (AudioServicesPropertyKey.IsUISound, sizeof (AudioServicesPropertyKey), &soundId, &out_size, &data);
+				}
 				if (res != AudioServicesError.None)
 					throw new ArgumentException (res.ToString ());
 
@@ -111,8 +115,12 @@ namespace AudioToolbox {
 
 			set {
 				uint data = value ? (uint) 1 : 0;
+				AudioServicesError res;
+				var soundId = this.soundId;
 
-				var res = AudioServices.AudioServicesSetProperty (AudioServicesPropertyKey.IsUISound, sizeof (AudioServicesPropertyKey), ref soundId, sizeof (uint), ref data);
+				unsafe {
+					res = AudioServices.AudioServicesSetProperty (AudioServicesPropertyKey.IsUISound, sizeof (AudioServicesPropertyKey), &soundId, sizeof (uint), &data);
+				}
 				if (res != AudioServicesError.None)
 					throw new ArgumentException (res.ToString ());
 			}
@@ -122,8 +130,11 @@ namespace AudioToolbox {
 			get {
 				uint out_size = sizeof (uint);
 				uint data;
-
-				var res = AudioServices.AudioServicesGetProperty (AudioServicesPropertyKey.CompletePlaybackIfAppDies, sizeof (AudioServicesPropertyKey), ref soundId, out out_size, out data);
+				AudioServicesError res;
+				var soundId = this.soundId;
+				unsafe {
+					res = AudioServices.AudioServicesGetProperty (AudioServicesPropertyKey.CompletePlaybackIfAppDies, sizeof (AudioServicesPropertyKey), &soundId, &out_size, &data);
+				}
 				if (res != AudioServicesError.None)
 					throw new ArgumentException (res.ToString ());
 
@@ -132,8 +143,11 @@ namespace AudioToolbox {
 
 			set {
 				uint data = value ? (uint) 1 : 0;
-
-				var res = AudioServices.AudioServicesSetProperty (AudioServicesPropertyKey.CompletePlaybackIfAppDies, sizeof (AudioServicesPropertyKey), ref soundId, sizeof (uint), ref data);
+				AudioServicesError res;
+				var soundId = this.soundId;
+				unsafe {
+					res = AudioServices.AudioServicesSetProperty (AudioServicesPropertyKey.CompletePlaybackIfAppDies, sizeof (AudioServicesPropertyKey), &soundId, sizeof (uint), &data);
+				}
 				if (res != AudioServicesError.None)
 					throw new ArgumentException (res.ToString ());
 			}
diff --git a/tests/cecil-tests/BlittablePInvokes.KnownFailures.cs b/tests/cecil-tests/BlittablePInvokes.KnownFailures.cs
index 89b5572cd0..90b2fadc70 100644
--- a/tests/cecil-tests/BlittablePInvokes.KnownFailures.cs
+++ b/tests/cecil-tests/BlittablePInvokes.KnownFailures.cs
@@ -76,8 +76,6 @@ namespace Cecil.Tests {
 			"AudioToolbox.AudioQueueStatus AudioToolbox.AudioQueueProcessingTap::AudioQueueProcessingTapGetSourceAudio(System.IntPtr,System.UInt32,AudioToolbox.AudioTimeStamp&,AudioToolbox.AudioQueueProcessingTapFlags&,System.UInt32&,System.IntPtr)",
 			"AudioToolbox.AudioQueueStatus AudioToolbox.OutputAudioQueue::AudioQueueOfflineRender(System.IntPtr,AudioToolbox.AudioTimeStamp&,AudioToolbox.AudioQueueBuffer*,System.Int32)",
 			"AudioToolbox.AudioQueueStatus AudioToolbox.OutputAudioQueue::AudioQueueSetOfflineRenderFormat(System.IntPtr,AudioToolbox.AudioStreamBasicDescription&,System.IntPtr)",
-			"AudioToolbox.AudioServicesError AudioToolbox.AudioServices::AudioServicesGetProperty(AudioToolbox.AudioServicesPropertyKey,System.UInt32,System.UInt32&,System.UInt32&,System.UInt32&)",
-			"AudioToolbox.AudioServicesError AudioToolbox.AudioServices::AudioServicesSetProperty(AudioToolbox.AudioServicesPropertyKey,System.UInt32,System.UInt32&,System.UInt32,System.UInt32&)",
 			"AudioToolbox.MusicPlayerStatus AudioToolbox.MusicSequence::MusicSequenceBarBeatTimeToBeats(System.IntPtr,AudioToolbox.CABarBeatTime,System.Double&)",
 			"AudioToolbox.MusicPlayerStatus AudioToolbox.MusicSequence::MusicSequenceBeatsToBarBeatTime(System.IntPtr,System.Double,System.Int32,AudioToolbox.CABarBeatTime&)",
 			"AudioToolbox.MusicPlayerStatus AudioToolbox.MusicSequence::MusicSequenceFileCreateData(System.IntPtr,AudioToolbox.MusicSequenceFileTypeID,AudioToolbox.MusicSequenceFileFlags,System.UInt16,System.IntPtr&)",
diff --git a/tests/monotouch-test/AudioToolbox/SystemSoundTest.cs b/tests/monotouch-test/AudioToolbox/SystemSoundTest.cs
index 59c8df597c..eed2ea1c39 100644
--- a/tests/monotouch-test/AudioToolbox/SystemSoundTest.cs
+++ b/tests/monotouch-test/AudioToolbox/SystemSoundTest.cs
@@ -53,6 +53,16 @@ namespace MonoTouchFixtures.AudioToolbox {
 			using (var ss = SystemSound.FromFile (NSUrl.FromFilename (path))) {
 				Assert.That (ss.IsUISound, Is.True, "#1");
 				Assert.That (ss.CompletePlaybackIfAppDies, Is.False, "#2");
+
+				ss.CompletePlaybackIfAppDies = true;
+				ss.IsUISound = false;
+				Assert.That (ss.IsUISound, Is.False, "#1 B");
+				Assert.That (ss.CompletePlaybackIfAppDies, Is.True, "#2 B");
+
+				ss.CompletePlaybackIfAppDies = false;
+				ss.IsUISound = true;
+				Assert.That (ss.IsUISound, Is.True, "#1 C");
+				Assert.That (ss.CompletePlaybackIfAppDies, Is.False, "#2 C");
 			}
 		}