Boot F-keys on Filco Minila

[do3e]

Hi, I've a Filco Minila and would like to know how can I input the F-keys at boot. For some reason it doesn't work. After boot I can input all the F's using the fn key, but when booting it doesn't trigger anything.
I've tried to press just the number, fn + number (this should work), both fn + number and I get nothing.

Any ideas on this? It seams to me very weird that a keyboard want give a chance to press F keys on boot time, as most of the BIOS triggers are F<something>

Thank you =)