Questions on setup and usage

We have a commerical application which we currently are running under a
different database but would like to consider a enterprise version using
PostGres.  There are several features in this other database that have
become important to us.

1.  The ability to encrypt stored procedures and triggers.  I know that
PostGres doesn't have this feature but is there a way to protect stored
procedure and trigger source yet allow it to be executed by any user and how
would it be done.

2.  We do not want the table schema to be accessed by outside applications. 
Since our application is so normalized, accessing these tables directly will
not make a lot of sense to our users so we create views that are more user
friendly for doing reports, accessing the data via Excel, etc.  How would we
do this in Postgres.

3.  We use active directory to validate a user's login.  We have "rules" and
functionality security built in as stored procedures. How would we do this
under Postgres.  We do this with a configuration variable during the login
process stored process.  If the company uses active directory we use it to
validate the user, if not then we present a user login and require that a
login be manually entered.  For those companies that use active directory we
try to have our application validate the AD so that the user isn't required
to multiple applications.

Best Regard

--
Michael Gould, Managing Partner
Intermodal Software Solutions, LLC
904.226.0978
904.592.5250 fax