passing keys from NPAPI plug-in to Firefox window

In our NPAPI plug-in, we get some keystrokes when in focus, but
certain browser specific key strokes e.g. Ctrl+T, Ctrl+B (and others),
we want to pass on to the browser window.
Posting the key messages to top level browser window doesn't seem to
help :(
I came across this mozilla bug: https://bugzilla.mozilla.org/show_bug.cgi?id=78414,
which is open since 2001 and no resolution as of now!
Does anybody know a workaround/solution for this?
I read somewhere that even in Javascript code, custom keyevents can't
be generated which browser can execute for us....