PostgreSQL 8.3.7: soundex function returns UTF-16 characters

Hello,

We have just discovered a problem with the soundex function in
PostgreSQL 8.3.7. The problem is easy to reproduce. The following query
returns the ASCII code of the soundex representation of the Greek letter Pi:

select ascii (soundex('Π'));

In PostgreSQL 8.2.6 the result would be 0 (character null). In
PostgreSQL 8.3.7 the return value is 944, which is the UTF-16 code of
this letter. Because PostgreSQL does not support UTF-16, this behaviour
causes problems when the return values from the soundex function are
stored in a database column. For instance, creating an index on such a
column or doing VACUUM FULL on the table results in errors like:

ERROR: could not convert string to UTF-16

Regards,
Frans