Ah I thought as much.. ;-) ( I mean that it was a DB version issue, not Perl or modules)

The constants.h file in the BerkeleyDB source references the functions; when you build the module, you end up with a shared library, BerkeleyDB.so -- once postgrey invokes BerkeleyDB,

use BerkeleyDB;
[download]

you've got access to all the functions..