Hi -
I did a quick review of our support tracks from recent years and I see very few mentions of PostgreSQL PostGIS. One track described how the PostgeSQL driver that we use does not really handle spatial PostGIS data types. Our documentation also does not call out that PostGIS objects are supported. You may be able to access some non-graphical data from the PostGIS extender. I see in one support track that using the MAX_TEXT_LEN connection parameter helped.
Ron