Transcoding problem with wine and unixodbc

I am still trying to excute a MFC application (working with psqlodbc
under WinXP) under wine, unix psqlodbc, and unixodbc.

My application is in ANSI, but the DB is in Unicode, so under Windows, I
use Postgrsql Unicode driver (which transcodes..?) without any  problem.
Under wine, I have tried the 2 drivers (psqlodbcw.so and psqlodbca.so)
and with the same incorrect result.
For exemple <è> becomes <Ã"> (in 2 characters).

Any hint welcome...