pgcrypto sha256/384/512 don't work on Redhat. Please help!

Hello,

Pgcrypto SHA 256/384/512 algorithm don't work on RedHat:

db=# SELECT digest('test', 'sha1');
digest
----------------------------------------------------------------------
\251J\217\345\314\261\233\246\034L\010s\323\221\351\207\230/\273\323
(1 row)

db=# SELECT digest('test', 'sha256');
ERROR: Cannot use "sha256": No such hash algorithm

I have standard Fedora Core 4 installed with standard PostgreSQL 8.1.3
Pgcrypto documentation says that it has built-in SHA256 and it should work
when OpenSSL is not found:

==============
Without OpenSSL, public-key encryption does not work, as pgcrypto does
not yet contain math functions for large integers.

Functionality built-in OpenSSL
----------------------------------------------------
MD5 yes yes
SHA1 yes yes
SHA256/384/512 yes since 0.9.8

=================

Fedora core has OpenSSL 0.9.7 installed by default. And it's not possible to
install 0.9.8 because of glibc conflict.

I suspect pgcrypto looks for SHA256 in OpeSSL lib when it should use
built-in.
SHA256 is working fine on Windows but on Redhat it fails. Maybe because
windows pgcrypto DLL is compiled statically with OpenSSL?

How to make pgcrypto use built-in sha256?

Thanks.