Generic methods for serializing and deserialzing xml files using streams followup

Recently I asked this question: Generic methods for serializing and deserialzing xml files using streams

However it has come to my attention that this gives me an (harmless) exception when trying to deserialize.

System.IO.FileNotFoundException occurred
  Message="Could not load file or assembly '[Containing Assembly of MyType].XmlSerializers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified."
  Source="mscorlib"
  FileName="[Containing Assembly of MyType].XmlSerializers, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null"
  FusionLog=""
  StackTrace:
   at System.Reflection.Assembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection)
   at System.Reflection.Assembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, Assembly locationHint, StackCrawlMark& stackMark, Boolean throwOnFileNotFound, Boolean forIntrospection)

It is a well known problem and most people would fix it by adding this to their csproj:

<Target Name="AfterBuild" DependsOnTargets="AssignTargetPaths;Compile;ResolveKeySource" Inputs="$(MSBuildAllProjects);@(IntermediateAssembly)" Outputs="$(OutputPath)$(_SGenDllName)">
   <!-- Delete the file because I can't figure out how to force the SGen task. -->
   <Delete
     Files="$(TargetDir)$(TargetName).XmlSerializers.dll"
     ContinueOnError="true" />
   <SGen
     BuildAssemblyName="$(TargetFileName)"
     BuildAssemblyPath="$(OutputPath)"
     References="@(ReferencePath)"
     ShouldGenerateSerializer="true"
     UseProxyTypes="false"
     KeyContainer="$(KeyContainerName)"
     KeyFile="$(KeyOriginatorFile)"
     DelaySign="$(DelaySign)"
     ToolPath="$(TargetFrameworkSDKToolsDirectory)"
     Platform="$(Platform)">
      <Output
       TaskParameter="SerializationAssembly"
       ItemName="SerializationAssembly" />
   </SGen>
</Target>

However I've tried something different namely:

public static T DeserializeObject<T>(this Stream stream) where T : IXmlSerializable
{
    Parameters.RequireNotNull(stream, "stream");

    using (var xmlTextReader = XmlReader.Create(stream))
    {
        var importer = new XmlReflectionImporter()
        var mapping = importer.ImportTypeMapping(typeof(T));
        var serializer = new XmlSerializer(mapping);

        T result = (T)serializer.Deserialize(xmlTextReader);
        stream.Close();
        return result;
    }
}

So my question, is this good code? is this a proper work around?