Analizando con Fivewin el objeto "AcroPDF.PDF.1", instalado en mi ordenador, me devuelve los metodos accesibles, o supuestamente, como siempre hay que decir en estos casos
STDCALL dispatch FUNC void QueryInterface( [in] PTR, [out] PTR )
STDCALL dispatch FUNC unsigned long AddRef()
STDCALL dispatch FUNC unsigned long Release()
STDCALL dispatch FUNC void GetTypeInfoCount( [out] PTR )
STDCALL dispatch FUNC void GetTypeInfo( [in] unsigned int, [in] unsigned long, [out] PTR )
STDCALL dispatch FUNC void GetIDsOfNames( [in] PTR, [in] PTR, [in] unsigned int, [in] unsigned long, [out] PTR )
STDCALL dispatch FUNC void Invoke( [in] int, [in] PTR, [in] unsigned long, [in] unsigned short, [in] PTR, [out] PTR, [out] PTR, [out] PTR )
STDCALL dispatch PROPERTYGET BSTR src()
STDCALL dispatch PROPERTYPUT void src( [in] BSTR )
STDCALL dispatch FUNC VARIANT_BOOL LoadFile( [in] BSTR )
STDCALL dispatch FUNC void setShowToolbar( [in] VARIANT_BOOL )
STDCALL dispatch FUNC void gotoFirstPage()
STDCALL dispatch FUNC void gotoLastPage()
STDCALL dispatch FUNC void gotoNextPage()
STDCALL dispatch FUNC void gotoPreviousPage()
STDCALL dispatch FUNC void setCurrentPage( [in] int )
STDCALL dispatch FUNC void goForwardStack()
STDCALL dispatch FUNC void goBackwardStack()
STDCALL dispatch FUNC void setPageMode( [in] BSTR )
STDCALL dispatch FUNC void setLayoutMode( [in] BSTR )
STDCALL dispatch FUNC void setNamedDest( [in] BSTR )
STDCALL dispatch FUNC void Print()
STDCALL dispatch FUNC void printWithDialog()
STDCALL dispatch FUNC void setZoom( [in] float )
STDCALL dispatch FUNC void setZoomScroll( [in] float, [in] float, [in] float )
STDCALL dispatch FUNC void setView( [in] BSTR )
STDCALL dispatch FUNC void setViewScroll( [in] BSTR, [in] float )
STDCALL dispatch FUNC void setViewRect( [in] float, [in] float, [in] float, [in] float )
STDCALL dispatch FUNC void printPages( [in] int, [in] int )
STDCALL dispatch FUNC void printPagesFit( [in] int, [in] int, [in] VARIANT_BOOL )
STDCALL dispatch FUNC void printAll()
STDCALL dispatch FUNC void printAllFit( [in] VARIANT_BOOL )
STDCALL dispatch FUNC void setShowScrollbars( [in] VARIANT_BOOL )
STDCALL dispatch FUNC VARIANT GetVersions()
STDCALL dispatch FUNC void setCurrentHightlight( [in] int, [in] int, [in] int, [in] int )
STDCALL dispatch FUNC void setCurrentHighlight( [in] int, [in] int, [in] int, [in] int )
STDCALL dispatch FUNC void postMessage( [in] VARIANT )
STDCALL dispatch PROPERTYGET VARIANT messageHandler()
STDCALL dispatch PROPERTYPUT void messageHandler( [in] VARIANT )
STDCALL dispatch FUNC void execCommand( [in] VARIANT )
Pero no veo el metodo SAVE, por lo que seguramente alguno de los anteriores ( quizás el ultimo, haya que investigarlo un poco más ), o incluso analizar el metodo src que dispone del SET/GET, pero no sé si es solo para asignar/leer el nombre del fichero o lo que utiliza.