Close PopUp (BSP_WD_CMPWB)

Hi experts,

I did create a new component which I display as a popup.

Now I would like to close this popup according to this guideline Issue in pop up close, CL_BSP_WD_WINDOW | ABAP, SAP, benX AG, benX….

I did create an outboundplug called "RETURN". But on calling  me->fire_outbound_plug( IV_OUTBOUND_PLUG   = 'RETURN' ) I get the error, that the method does not exist or is private/protected.

What is my error?

Kind regards