diff --git a/include/propidl.idl b/include/propidl.idl
index a5d38125810..be0b7c04e96 100644
--- a/include/propidl.idl
+++ b/include/propidl.idl
@@ -386,3 +386,14 @@ cpp_quote("HRESULT WINAPI PropVariantCopy(PROPVARIANT*,const PROPVARIANT*);");
 cpp_quote("")
 cpp_quote("#define _PROPVARIANT_INIT_DEFINED_")
 cpp_quote("#define PropVariantInit(p) memset((p), 0, sizeof(PROPVARIANT))")
+cpp_quote("")
+cpp_quote("#ifndef _STGCREATEPROPSTG_DEFINED_")
+cpp_quote("#define _STGCREATEPROPSTG_DEFINED_")
+cpp_quote("HRESULT WINAPI StgCreatePropStg(IUnknown *, REFFMTID, const CLSID *, DWORD, DWORD, IPropertyStorage **);");
+cpp_quote("HRESULT WINAPI StgOpenPropStg(IUnknown *, REFFMTID, DWORD, DWORD, IPropertyStorage **);");
+cpp_quote("HRESULT WINAPI StgCreatePropSetStg(IStorage *, DWORD, IPropertySetStorage **);");
+cpp_quote("#define CCH_MAX_PROPSTG_NAME 31");
+cpp_quote("HRESULT WINAPI FmtIdToPropStgName(const FMTID *, LPOLESTR);");
+cpp_quote("HRESULT WINAPI PropStgNameToFmtId(const LPOLESTR, FMTID *);");
+cpp_quote("#endif /* _STGCREATEPROPSTG_DEFINED_ */");
+cpp_quote("")