Hi Jorn,
  I think that this is the wrong place to add this request.

  There are two options, the first is to submit the request to the lyx developers, the changes are small and it should be an easy process.

  In case they reject that, it would be possible to submit a new fedora package that requires lyx and installs the icons at the appropriate place.

  In any case this is not something that IMHO should be done in the lyx package.