diff --git a/build/vc100/turtle.vcxproj b/build/vc100/turtle.vcxproj
index 536b960..c358010 100644
--- a/build/vc100/turtle.vcxproj
+++ b/build/vc100/turtle.vcxproj
@@ -50,6 +50,7 @@
     <ClInclude Include="..\..\turtle\log.hpp" />
     <ClInclude Include="..\..\turtle\mock.hpp" />
     <ClInclude Include="..\..\turtle\object.hpp" />
+    <ClInclude Include="..\..\turtle\object_impl.hpp" />
     <ClInclude Include="..\..\turtle\sequence.hpp" />
   </ItemGroup>
   <PropertyGroup Label="Globals">
diff --git a/build/vc100/turtle.vcxproj.filters b/build/vc100/turtle.vcxproj.filters
index 4a65982..13e2769 100644
--- a/build/vc100/turtle.vcxproj.filters
+++ b/build/vc100/turtle.vcxproj.filters
@@ -106,5 +106,8 @@
     <ClInclude Include="..\..\turtle\detail\operators.hpp">
       <Filter>Source Files\detail</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\turtle\object_impl.hpp">
+      <Filter>Source Files</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>
\ No newline at end of file
diff --git a/turtle/object.hpp b/turtle/object.hpp
index c375d6a..11180b9 100644
--- a/turtle/object.hpp
+++ b/turtle/object.hpp
@@ -9,16 +9,14 @@
 #ifndef MOCK_OBJECT_HPP_INCLUDED
 #define MOCK_OBJECT_HPP_INCLUDED
 
+#include "object_impl.hpp"
 #include "detail/root.hpp"
-#include "detail/parent.hpp"
 #include "detail/type_name.hpp"
-#include "detail/context.hpp"
-#include "detail/child.hpp"
 #include <boost/test/utils/basic_cstring/basic_cstring.hpp>
-#include <boost/enable_shared_from_this.hpp>
 #include <boost/type_traits/is_base_of.hpp>
 #include <boost/utility/enable_if.hpp>
 #include <boost/shared_ptr.hpp>
+#include <boost/optional.hpp>
 
 namespace mock
 {
@@ -26,73 +24,13 @@ namespace mock
     {
     public:
         object()
-            : impl_( new object_impl() )
+            : impl_( new detail::object_impl() )
         {}
-
     protected:
         ~object()
         {}
-
-    private:
-        class object_impl : public detail::context, public detail::verifiable,
-            public boost::enable_shared_from_this< object_impl >
-        {
-        public:
-            virtual void add( const void* /*p*/, detail::verifiable& v,
-                boost::unit_test::const_string instance,
-                const boost::optional< detail::type_name >& type,
-                boost::unit_test::const_string name )
-            {
-                if( children_.empty() )
-                    mock::detail::root.add( *this );
-                children_[ &v ].update( parent_, instance, type, name );
-            }
-            virtual void add( detail::verifiable& v )
-            {
-                group_.add( v );
-            }
-            virtual void remove( detail::verifiable& v )
-            {
-                group_.remove( v );
-                children_.erase( &v );
-                if( children_.empty() )
-                    mock::detail::root.remove( *this );
-            }
-
-            virtual void serialize( std::ostream& s,
-                const detail::verifiable& v ) const
-            {
-                children_cit it = children_.find( &v );
-                if( it != children_.end() )
-                    s << it->second;
-                else
-                    s << "?";
-            }
-
-            virtual bool verify() const
-            {
-                return group_.verify();
-            }
-            virtual void reset()
-            {
-                boost::shared_ptr< object_impl > guard = shared_from_this();
-                group_.reset();
-            }
-
-        private:
-            typedef std::map<
-                const detail::verifiable*,
-                detail::child
-            > children_t;
-            typedef children_t::const_iterator children_cit;
-
-            detail::group group_;
-            detail::parent parent_;
-            children_t children_;
-        };
-
     public:
-        boost::shared_ptr< object_impl > impl_;
+        boost::shared_ptr< detail::object_impl > impl_;
     };
 
 namespace detail
diff --git a/turtle/object_impl.hpp b/turtle/object_impl.hpp
new file mode 100644
index 0000000..4047154
--- /dev/null
+++ b/turtle/object_impl.hpp
@@ -0,0 +1,85 @@
+// http://turtle.sourceforge.net
+//
+// Copyright Mathieu Champlon 2012
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef MOCK_OBJECT_IMPL_HPP_INCLUDED
+#define MOCK_OBJECT_IMPL_HPP_INCLUDED
+
+#include "detail/root.hpp"
+#include "detail/parent.hpp"
+#include "detail/type_name.hpp"
+#include "detail/context.hpp"
+#include "detail/child.hpp"
+#include <boost/test/utils/basic_cstring/basic_cstring.hpp>
+#include <boost/enable_shared_from_this.hpp>
+#include <boost/shared_ptr.hpp>
+#include <boost/optional.hpp>
+
+namespace mock
+{
+namespace detail
+{
+    class object_impl : public detail::context, public detail::verifiable,
+        public boost::enable_shared_from_this< object_impl >
+    {
+    public:
+        virtual void add( const void* /*p*/, detail::verifiable& v,
+            boost::unit_test::const_string instance,
+            const boost::optional< detail::type_name >& type,
+            boost::unit_test::const_string name )
+        {
+            if( children_.empty() )
+                mock::detail::root.add( *this );
+            children_[ &v ].update( parent_, instance, type, name );
+        }
+        virtual void add( detail::verifiable& v )
+        {
+            group_.add( v );
+        }
+        virtual void remove( detail::verifiable& v )
+        {
+            group_.remove( v );
+            children_.erase( &v );
+            if( children_.empty() )
+                mock::detail::root.remove( *this );
+        }
+
+        virtual void serialize( std::ostream& s,
+            const detail::verifiable& v ) const
+        {
+            children_cit it = children_.find( &v );
+            if( it != children_.end() )
+                s << it->second;
+            else
+                s << "?";
+        }
+
+        virtual bool verify() const
+        {
+            return group_.verify();
+        }
+        virtual void reset()
+        {
+            boost::shared_ptr< object_impl > guard = shared_from_this();
+            group_.reset();
+        }
+
+    private:
+        typedef std::map<
+            const detail::verifiable*,
+            detail::child
+        > children_t;
+        typedef children_t::const_iterator children_cit;
+
+        detail::group group_;
+        detail::parent parent_;
+        children_t children_;
+    };
+}
+} // mock
+
+#endif // MOCK_OBJECT_IMPL_HPP_INCLUDED