Changing ODBC users with Access doesn't work correctly for me

I'm using Access2000 on Win98 as a postgresql frontend with the odbc driver.

Problem 1:
With the driver downloaded in January (using postgresql 7.0.x), I had the
following (annoying) behaviour:
When loading the access frontend, the odbc driver input form pops up when I
try to access the first table (which is intended). However, when I try to
change the user name (to y), the connection will still be tried with the
user (x) that was entered into the odbc drivers in the system settings. The
connection will likely fail, because y's password is sent along with x's
user id. To be able to connect as a differnt user, one has to change the
odbc systems setting in the control panel.

Problem 2 (prob 1 enhanced)
But now this reluctance to change users is becoming a nuisance:
I upgraded to postgresql 7.1.2 and installed the newest odbc driver.
I started a new access file, and if I try to connect, the connection will be
tried with the name of the user that linked the list in the first place,
instead of the user given in the popup-form (the correct one), or the user
given in the control panel settings (the version that worked before).

Does anybody have a suggestion how this behaviour can be changed?

Regards
Alex Rhomberg