> Not possible. For some reasons server does not allow seeking back the
> stream.

Ups, sorry... Seems that I was to fast. I am sure that server does not
allow seeking back the output stream. You have to check the input
stream. Current version of the driver in CVS exports method seek (see
org.firebirdsql.jdbc.FirebirdBlob interface), and there are already
test cases that you can easily extend.

It it works, than just add reset() method to corresponding interfaces
and implementation that would call seek(...) internally.

Roman