How to set compatible property for a connection?

I need to find out how to set the "compatible" property for a connection as
described in Section 5.6 "Storing Binary Data" in the PostgreSQL 7.3
Documentation. I want to revert the driver back to 7.1 functionality.

I've not been able to find any other discussion of the "compatible" property
in any of the PostgreSQL docs, including Rene Pijlman's page.

Thanks,

--BobC