Connection string parameter "sslrootcert" does not work

Hi,
I am using the psqlODBC driver to connect to Amazon RDS. I am able to
connect successfully after enabling SSL encryption via the connection
string parameter "sslmode=require". I want to now enable verification of
server identity too, which means that I need to provide the CA certificate
path to the Postgres driver. I tried the connection parameters
"sslmode=verify-full;sslrootcert=<path to CA file>", but the driver is not
able to pick up the file from the specified path (I tried on Windows and
Mac OS X). Things work, however, when the certificate is placed in the
default place the driver looks in - %APPDATA%\Roaming\postgresql\root.crt
on Windows; ~/.postgresql/root.crt on Mac.

Is this a bug that needs to be fixed or am I doing something wrong? I
am using psqlodbc version 09_03_0300-1.

Thanks,
Ed

The resources I consulted:
http://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_PostgreSQL.html#PostgreSQL.Concepts.General.SSL
http://www.postgresql.org/docs/9.3/static/libpq-ssl.html
http://www.postgresql.org/docs/9.3/static/libpq-connect.html