I( have done a little research on the used protocol in the Honda key and came to the following conclusion:
MY EU US 00 MEGAMOS Fixed13 ??? 01 MEGAMOS Fixed13 MEGAMOS 48 02 MEGAMOS Fixed13 MEGAMOS 48 03 MEGAMOS 13 MEGAMOS 48 04 MEGAMOS 13 MEGAMOS 48 05 MEGAMOS 13 MEGAMOS 48 06 MEGAMOS 8E MEGAMOS 8E 07 MEGAMOS 8E MEGAMOS 8E 08 MEGAMOS 8E MEGAMOS 8E 09 MEGAMOS 8E MEGAMOS 8E
MEGAMOS 13 is also known as TP05.
This explains the Honda US category as it is not in line with EU vehicles.
This I think explains the issue. The key I bought (35113-S84-A02) is not compatible with European ECU's.