use UMG widget class to create custom widget

I want to create custom widget, that i can use with graphical ui designer.
so i created new class that inherit from UWidget
next created method virtual TSharedRef<SWidget> RebuildWidget() override.
and with this i already made some simple widget like text, button, with comand myButton = SNew(SButton)
and return myButton.ToSharedRef()

but now i wonder if need all functionality from UButton, can I create instance of Ubutton in my custom widget and use it?
i think copy evrything or almost evrything from Ubutton to my widget is a little stupid idea, but to work with RebuildWidget
i need Swidget no Uwidget
is it possible to make button appear in graphic design?

pls help