getting to /usr but not /compat/usr from a linux app

[Fernan Aguero]

I'm using Linux Firefox, and when asked to choose a helper
app to open a document I try to navigate to /usr/X11R6/bin
but I always end up in /compat/linux/usr/X11R6/bin instead
(though firefox believes it's /usr/X11R6/bin).

I can see why this happens (linux apps should be fooled into
using their 'compat' usr space), but is there any way of
escaping from this?

Thanks,

Fernan