I'm not sure what you are expecting but...
> SELECT * FROM test WHERE source_content ILIKE '%accept%'; ---> returns a record
> SELECT * FROM test WHERE source_content ILIKE '%accepté%' ---> returns a record
> SELECT * FROM test WHERE source_content ILIKE '%accepte%' ---> returns 0 record
So all of above seem to work fine for me.
$ pg_config --configure
--prefix=/usr/local/pgsql --enable-multibyte=EUC_JP --enable-unicode-conversion --with-tcl --with-perl --enable-syslog
--enable-debug--with-CXX --with-java
$ pg_config --version
PostgreSQL 7.1.3
--
Tatsuo Ishii