I used this Emblem. It fits perfectly on the generic 'momo' horn buttons, the cheap ones. One can remove the plastic doomed Sticker in the Center and replaced IT with the emblem.
Horn button Like this: https://www.ebay.com/itm/16370...tkp%3ABk9SR6KFyo-5YQ
Attention: IT does Not Work with the original Momo buttons. They habe a different center Part.