Index: /trunk/src/VBox/Main/GuestImpl.cpp
===================================================================
--- /trunk/src/VBox/Main/GuestImpl.cpp	(revision 29590)
+++ /trunk/src/VBox/Main/GuestImpl.cpp	(revision 29591)
@@ -227,4 +227,16 @@
 
     return S_OK;
+}
+
+STDMETHODIMP Guest::COMSETTER(PageFusionEnabled) (BOOL aPageFusionEnabled)
+{
+    AutoCaller autoCaller(this);
+    if (FAILED(autoCaller.rc())) return autoCaller.rc();
+
+    AutoWriteLock alock(this COMMA_LOCKVAL_SRC_POS);
+
+    /** todo; API complete, but not implemented */
+
+    return E_NOTIMPL;
 }
 
Index: /trunk/src/VBox/Main/idl/VirtualBox.xidl
===================================================================
--- /trunk/src/VBox/Main/idl/VirtualBox.xidl	(revision 29590)
+++ /trunk/src/VBox/Main/idl/VirtualBox.xidl	(revision 29591)
@@ -8497,5 +8497,5 @@
   <interface
      name="IGuest" extends="$unknown"
-     uuid="25efde01-dd0b-43b0-9ceb-e4e6307107ac"
+     uuid="d915dff1-ed38-495a-91f1-ab6c53932468"
      wsmap="managed"
      >
@@ -8562,5 +8562,5 @@
     </attribute>
 
-    <attribute name="pageFusionEnabled" type="boolean" readonly="yes">
+    <attribute name="pageFusionEnabled" type="boolean">
       <desc>Flag whether page fusion is enabled or not.</desc>
     </attribute>
Index: /trunk/src/VBox/Main/include/GuestImpl.h
===================================================================
--- /trunk/src/VBox/Main/include/GuestImpl.h	(revision 29590)
+++ /trunk/src/VBox/Main/include/GuestImpl.h	(revision 29591)
@@ -83,4 +83,5 @@
     STDMETHOD(COMSETTER(MemoryBalloonSize)) (ULONG aMemoryBalloonSize);
     STDMETHOD(COMGETTER(PageFusionEnabled)) (BOOL *aPageFusionEnabled);
+    STDMETHOD(COMSETTER(PageFusionEnabled)) (BOOL aPageFusionEnabled);
     STDMETHOD(COMGETTER(StatisticsUpdateInterval)) (ULONG *aUpdateInterval);
     STDMETHOD(COMSETTER(StatisticsUpdateInterval)) (ULONG aUpdateInterval);