Peter,

have you tried using AssignTo ?
e.g. IB_Query_Templates.FieldByName('TEMPLATE').AssignTo(Storage);

You said "text blob" - with IBObjects you can read/write columns defined as
"MemoColumn BLOB SUB_TYPE TEXT" using FieldByName('MemoColumn').AsString.

Also have a look at the example code in the help for
TIB_Statement.CreateBlobStream.

HTH,
Markus