Perhaps I have missed something here -- I don't
think I've seen the entire thread -- but perhaps you
could achieve your objective by placing the following
line at the beginning (i.e., *first* line) of your shell script:

#!/usr/local/bin/osh

Then your entire shell script will (should) be executed
by osh.

I wouldn't really know, though, as I have never seen a
system where "osh" was actually used.  Usually
I set the "ulimits" appropriately high for *all* necessary
users, and pretty much every database server I have
seen in years does the same...

(Actually, I usually set the ulimits for *all* users on
the database server, but in my universe, only DBAs
and sysadmins ever login to the database server.
Usually, at least.  With modern UNIXEN where kernel
resources are allocated dynamically, there is much
less reason *not* to do this than there was 10 years
ago...)

Anyway, this might work for you.  Good luck.



--
Cheers,
-- Mark Brinsmead
   Staff DBA,
   The Pythian Group
   http://www.pythian.com/blogs