The dealer could be holding the key to the key problem…
Do you know if they consulted any Kia Technical Service Bulletins? I would ask if you don’t know.
5 page Kia Technical Service Bulletin #KT2005022529 (with matrix charts) was written to assist Kia Technicians with replacing keys and has instructions for situations where the key code is known and where the key code is unknown.
However, the charts in the bulletin give information for models other than Amanti. For the 2004 Amanti the bulletin charts say:
"Until Further Notice: Contact Kia Technical Assistance for duplication instruction procedures 1 800 494-4542."
CSA