in reply to
Custom SQL in DBIx::Class (or how to use PgSQL fulltext search from Perl)
Not sure on the SQL::Abstract approach (you could try the DBIC mailing list, or the channel on irc.perl.org), but I've found one way around this when SQL::Abstract won't cut the mustard is to create a ResultSet class, get the DBI object, and manually execute a query.
The main downside is you don't get back objects (altho I think it might be possible to construct them). SQL abstraction is nice, but not always the best approach.