Informix CLI Passwords to UNIX server

I have Informix CLI V2.5 for NT, and I am trying to set it up as the ODBC driver to an Informix 7.12 database on an AIX system. The problem comes with passwords. Informix on AIX expects NO PASSWORD. Not a blank password, but NO password. There is no problem setting this up for I-connect; setnet32 properly understands the NO PASSWORD option and the connection is okay. ESQL/C programs run properly. CLI (or its ODBC setup) doesn't seem to use the database sources set up with setnet32. It wants to ask for the username and password when the ODBC application (Access) connects, and it doesn't understand NO PASSWORD. Blank password results in the infamous -952. So does the correct password. I don't see anything in the registry begging to be set. The manuals that came with the product are of their usual value. And I didn't see anything pertinent in the FAQ. Client is NT 4.0 SP3, with Access 97. Server is AIX3.25, on a RS/6000, Informix 7.12. TCP/IP network. Any hints on where to bang on it? Finding a different ODBC product isn't an option at this time. Thanks in advance, dwight