How to derive new class from TField ?

The Sybase SQL-Anywhere DBMS does not support the boolean-type. It is
implemented as a integer-subtype BIT. The BDE does not recognize this
type as Boolean. So the field-editor in Delphi creates a TSmallIntField.
My idea is, to derive a new TMyBoolean-class from TSmallIntField and to
override the Get- and SetBoolean-methods.
But: How can I access this type in the field-editor, or in the
"datamodule-as-text-editor" ?
Do someone have a better idea to get a type-conform component in Delphi