Subject WHERE clause or filter with non-ASCII values always send in UTF-8


I'm using IBO 4.9.14 build 50 with Delphi 7. TIBODataset.CharSet is set to 'ISO8859_1'.

If I use non-ASCII characters (most time German Umlaut like ä, ö or ü) in a WHERE clause or in the filter property they are always send UTF-8 coded to the Firebird server, as I can see with the trace option. In result, the desired records are not found.

Here an example:

Part of the SQL Where: ... AND J.LIEFERANT = 'Österreichischer Wirtscha' ...

Part of Firebird trace: … AND J.LIEFERANT = 'Österreichischer Wirtscha' ...

If I pass the search values as Parameters to the server all works as expected.

Unfortunately it hard to change my application to use only Parameter. Is there any work around to send filter or WHERE parts of an SQL Statement not in UTF-8 but in the coding set in TIBODataset?