Clearer now!
Upon closer inspection, the reference guide specicifally says:
Back Reference: Click this button to access the Back Reference dialog box. If the current drawing is based on a
source marker, then this dialog box will list any Layout whose Drawing displays the
source marker of the current drawing.
So it looks like we're SOL. I guess there's some ugly workarounds, like placing minute drawings on layouts for referencing, but you'd have to be pretty keen!
Cheers,
Link.