With the new driver I sometimes see messages being printed to stderr, obviously the ODBC driver should not do this.
I believe the PQnoticeProcessor needs to be set, see this documentation for details of how this works.
http://www.postgresql.org/docs/7.4/interactive/libpq-notice-processing.html
It should be trivial to add this but I'm not sure what the best place to do it would be, would one of the maintainers be able to do it?