Upgrade flipkeys how?

Hello together, I need a plan! After the original rubber key of my V70II has turned into a black, sticky chewing gum clump, I remember the ‘then read here thread, a flipkey of the newer models (my is EZ 02/2003), to retrofit. Original of the friendly does not work of course. In the thread from 2006 it was advised to get a flipkey from the USA, to order the bowl blade here at the friendly fitting to the FG-No. and to screw the board from the old remote control into the Ami- flipkey. Sounds quite good so far, I would like to do so, my problem is that the flipkeys that are offered in the USA always have 5 keys, e.g. at “midwestkeyless”. My remote control has however only 4 keys, the red triangle is missing. Therefore my question, whether this conversion really has a chance to work out. Maybe someone has already tried it out before me. The rubber keys may now be in resolution, actually a shame for a car, or a premium.