Well, after all it was not such an act. I've taken the 09.03 sources of psqlodbc, installed the unixODBC-devel package for the include files, then make went through and isql accepted the /usr/local/lib/psqlodbcw.so. I've copied it to Hana exe directory and in ~hdbadm/.odbc.ini I've included
Driver = psqlodbcw.so
and this worked. Mind you, I had to restart Hana because it would still write the message that it cannot find the driver file that I've specified earlier, although it was no longer specified in the .odbc.ini file, and in strace it really first read the .odbc.ini file and then went looking for the driver that was no longer in it! Probably some (bad) caching involved.
Thanks a lot for your help.
-- Micha