Hi David,
I solved going to the properties in the GUI that I have in the background (A), clicking in the properties of this button that I want to execute.
There is a code which appears in the field Callback
Finally I put this code in the button of GUI B, and works!
GUI_A('pushbutton1_Callback',gcbo,[],guidata(gcbo))
close %close GUI_B
Of course I must use "getappdata" and "setappdata2 to move the data between GUIs
:D