I THINKS,
You can use a ODBC for Informix, When you installed a Informix Client SDK , it install a ODBC for you.
Create new DSN (In ODBC)
Setup Configure :
* Server Name = {Your Informix Server, $INFORMIXSERVER }
- Host Name = {Informix Server Hostname }
- Services = {Services name in 'services' file for Informix Connection }
- Protocol = {Use 'onsoctcp' for TCP/IP Connection}
- Database Name = {Enter your database name}
######## TRY IT! #######