Firebird SQL, replace issue

Hi All,
Wondering if anyone could help me with a problem I have with a Firebird 1.5 database,

One of our tables called 'client' has a column called 'Address' and contains street names, some of the fields contain a character that is causing us issues, this is the Finnish letter 'Ä', I would like to be able to search this table and replace the 'Ä' character with 'ä'.

Is there anyone who could tell me what Firebird SQL script would work with firebird to find and replace a single character within a field that contains a street name such as the one above.

I don't use Firebird SQL very much and I'm having trouble resolving this issue, so any help would be greatly appreciated.

Regards Alan

There is a REPLACE() function in FB2.1
Try to upgrade your db

EDIT ;
Get a copy of FreeUdfLib , it have the F_Replace() function for you and more...

regards