Hi all,
I found the necessary magic to make it all work:

	BUILDLINK_PREFIX.openssl=       /opt/SUNWconn/crypto
	BUILDLINK_IS_DEPOT.openssl=     YES


PREFIX is the obvious one that I had already tried. IS_DEPOT is the magic that 
tells buildlink to tell the wrapper that the PREFIX is not under pkgsrc control 
and that it shouldn't make any assumptions about it. i.e. it tells pkgsrc that 
the named package is a third party package.

Cheers
-- 
Lloyd Parkes
Senior Systems Programmer
Open Systems
Ph: +64 4 890 2437