diff --git a/dlls/ole32/ole32.spec b/dlls/ole32/ole32.spec
index 8e73fdd16b4..08e15fd3d8b 100644
--- a/dlls/ole32/ole32.spec
+++ b/dlls/ole32/ole32.spec
@@ -187,7 +187,7 @@
 @ stdcall Ole32DllGetClassObject(ptr ptr ptr)
 @ stdcall OleBuildVersion()
 @ stdcall OleConvertIStorageToOLESTREAM(ptr ptr)
-@ stub OleConvertIStorageToOLESTREAMEx
+@ stdcall OleConvertIStorageToOLESTREAMEx(ptr long long long long ptr ptr)
 @ stdcall OleConvertOLESTREAMToIStorage(ptr ptr ptr)
 @ stub OleConvertOLESTREAMToIStorageEx
 @ stdcall OleCreate(ptr ptr long ptr ptr ptr ptr)
diff --git a/dlls/ole32/storage32.c b/dlls/ole32/storage32.c
index 3d372af83f5..706655ebd17 100644
--- a/dlls/ole32/storage32.c
+++ b/dlls/ole32/storage32.c
@@ -10595,6 +10595,17 @@ enum stream_1ole_flags {
     OleStream_Convert      = 0x00000004
 };
 
+/*************************************************************************
+ * OleConvertIStorageToOLESTREAMEx [OLE32.@]
+ */
+HRESULT WINAPI OleConvertIStorageToOLESTREAMEx ( LPSTORAGE stg, CLIPFORMAT cf, LONG width, LONG height,
+                                                 DWORD size, LPSTGMEDIUM medium, LPOLESTREAM olestream )
+{
+    FIXME("%p %x %d %d %d %p %p stub\n", stg, cf, width, height, size, medium, olestream);
+
+    return E_NOTIMPL;
+}
+
 /***********************************************************************
  *		GetConvertStg (OLE32.@)
  */
diff --git a/include/ole2.h b/include/ole2.h
index 05c1b5502c7..628bebae137 100644
--- a/include/ole2.h
+++ b/include/ole2.h
@@ -161,6 +161,8 @@ typedef struct _OLESTREAM {
 
 HRESULT     WINAPI OleConvertOLESTREAMToIStorage( LPOLESTREAM lpolestream, LPSTORAGE pstg, const DVTARGETDEVICE* ptd);
 HRESULT     WINAPI OleConvertIStorageToOLESTREAM( LPSTORAGE pstg, LPOLESTREAM lpolestream);
+HRESULT     WINAPI OleConvertIStorageToOLESTREAMEx( LPSTORAGE stg, CLIPFORMAT cf, LONG width, LONG height,
+                                                    DWORD size, LPSTGMEDIUM medium, LPOLESTREAM olestream );
 
 HRESULT     WINAPI OleDoAutoConvert( LPSTORAGE pStg, LPCLSID pClsidNew );
 HRESULT     WINAPI OleGetAutoConvert( REFCLSID clsidOld, LPCLSID pClsidNew );