What is the type of blob, is it a BLOB SUB_TYPE BINARY, or a BLOB
SUB_TYPE TEXT? In any case, the actual problems with characters being
replaced by a dot sounds like a problem with your component (or a
mismatch between character sets). Try casting explicitly casting with
the actual character set of the test data. For example if the data is
UTF8, use:
cast( MYBLOBFIELD as VARCHAR(4096) character set UTF8 )
Also make sure your component actual correctly shows the desired
characters. In some cases, your actual connection character set may also
be of influence.
Mark