do you just want a shorter reference to it for ease of coding? I'm pretty sure you should be able to use
var objFCO = window.opener.document.theFCO;
I know you can do it with some objects in js, but I'm not sure if it can be done with all of them.
what is 'theFCO'? a form?
how about
var objDoc = window.opener.document;
then use objDoc.theFCO
??
hhmmm, been awhile since I coded much... time for a new project!
g'luck vass! I'll check back.