diff --git a/plist-cil.test/BinaryPropertyListWriterTests.cs b/plist-cil.test/BinaryPropertyListWriterTests.cs
index 3433949..22d54ac 100644
--- a/plist-cil.test/BinaryPropertyListWriterTests.cs
+++ b/plist-cil.test/BinaryPropertyListWriterTests.cs
@@ -37,5 +37,37 @@ namespace plistcil.test
                 writer.Write(root);
             }
         }
+
+        [Fact]
+        public void Roundtrip3Test()
+        {
+            byte[] data = File.ReadAllBytes("test-files/plist3.bin");
+            NSObject root = PropertyListParser.Parse(data);
+
+            using (MemoryStream actualOutput = new MemoryStream())
+            using (Stream expectedOutput = File.OpenRead("test-files/plist3.bin"))
+            using (ValidatingStream validatingStream = new ValidatingStream(actualOutput, expectedOutput))
+            {
+                BinaryPropertyListWriter writer = new BinaryPropertyListWriter(validatingStream);
+                writer.ReuseObjectIds = false;
+                writer.Write(root);
+            }
+        }
+
+        [Fact]
+        public void Roundtrip4Test()
+        {
+            byte[] data = File.ReadAllBytes("test-files/plist4.bin");
+            NSObject root = PropertyListParser.Parse(data);
+
+            using (MemoryStream actualOutput = new MemoryStream())
+            using (Stream expectedOutput = File.OpenRead("test-files/plist4.bin"))
+            using (ValidatingStream validatingStream = new ValidatingStream(actualOutput, expectedOutput))
+            {
+                BinaryPropertyListWriter writer = new BinaryPropertyListWriter(validatingStream);
+                writer.ReuseObjectIds = false;
+                writer.Write(root);
+            }
+        }
     }
 }
diff --git a/plist-cil.test/plist-cil.test.csproj b/plist-cil.test/plist-cil.test.csproj
index c7698c2..cb0a71d 100644
--- a/plist-cil.test/plist-cil.test.csproj
+++ b/plist-cil.test/plist-cil.test.csproj
@@ -119,6 +119,12 @@
     <None Update="test-files\plist2.bin">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
+    <None Update="test-files\plist3.bin">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+    <None Update="test-files\plist4.bin">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
     <None Update="test-files\RoundtripBinaryIndentation.plist">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
     </None>
diff --git a/plist-cil.test/test-files/plist3.bin b/plist-cil.test/test-files/plist3.bin
new file mode 100644
index 0000000..1a7f751
Binary files /dev/null and b/plist-cil.test/test-files/plist3.bin differ
diff --git a/plist-cil.test/test-files/plist4.bin b/plist-cil.test/test-files/plist4.bin
new file mode 100644
index 0000000..0c1a127
Binary files /dev/null and b/plist-cil.test/test-files/plist4.bin differ
diff --git a/plist-cil/BinaryPropertyListWriter.cs b/plist-cil/BinaryPropertyListWriter.cs
index 1c7641d..4f14952 100644
--- a/plist-cil/BinaryPropertyListWriter.cs
+++ b/plist-cil/BinaryPropertyListWriter.cs
@@ -422,13 +422,18 @@ namespace Claunia.PropertyList
                 || content == "$classname"
                 || content == "NS.objects"
                 || content == "NS.keys"
+                || content == "NS.base"
+                || content == "NS.relative"
+                || content == "NS.string"
                 || content == "NSURL"
                 || content == "NSDictionary"
                 || content == "NSObject"
                 || content == "NSMutableDictionary"
                 || content == "NSMutableArray"
                 || content == "NSArray"
-                || content == "NSUUID";
+                || content == "NSUUID"
+                || content == "NSKeyedArchiver"
+                || content == "NSMutableString";
         }
 
         internal static bool IsSerializationPrimitive(NSNumber n)