press a button using UIAccessor help

How can i press a button via mxs using UIAccessor ? I am not quite understand from the mxs help how does this work. I want to launch the Scale Curve Editor from the Path Deform / Driven Scale (max 2018 update2)

i am stuck with this:

Fn openwin o =(	
maxHWND = windows.getMaxHWND()
setCommandPanelTaskMode #modify	
modPanel.setCurrentObject o.modifiers[#Path_Deform]
children = windows.GetChildrenHwnd maxHWND
-- What is the next step? I cannot find in listener the button name..
)

obj = selection[1]
for o in selection do (print (openwin o))

Thank you!