I drilled the three holes in the firewall recess before thinking about the final solution. I don't like the suggested solution by VANS and italian regulation require different pass through solution. For this reason i had to ask support to Lucio to drill out the installed recess and to adapt a new recess in order to accomodate the passthrough with SPHERE STEEL GROMMET.
Lucio has done a perfect job in adapting the firewall recess.