Calling Screen from the Application Toolbar button press in VA01

Hi,

I put one button in Application Toolbar in SAPMV45B-UMAT "GUI status". Whenever user clicks this button need to call the standard screen 800(Availability Display Screen for Several Items) in SAPMV45A. Is that possible to call standard screen in VA01 or need to create Zscreen as a copy of standard one .?

How i can call this screen??