You need some kind of event to fire a !bang command, or script it.

If you have opacity set to 1 in a themevars, like

opacity 1

and have

IF opacity = 1
xPopupAlphaTransparency 255
ENDIF

in with your popup definitions, then it will be set to 255 when you start LS or recycle. No need for a !bang in that situation.

You could also do

IF opacity = 1
xPopupAlphaTransparency 255
ELSEIF opacity = 2
xPopupAlphaTransparency othernumber
ENDIF

and so on.