2 years ago I made customer class, working with Interbase and Oracle, I can send you it. It work through odbc, Unfortunatly all forms in the project have russian captions. If you don't care, I can send you all project, it does all for Interbase, look server tables structures, import dbf into interbase, makes generators and triggers for setting primary fields, looks tables structure . It is described 2 years ago in newsletters on www.vfug.org
Best wishes< Vladimir Zhuravlev.