European "mirror" of the DO-178B is called ED-12B. It is just a copy, since the DO-178B was
developed by both RTCA and EUROCAE.
DO-178B "name" is widely used in EU. We used to name DO-178B instead ED-12B all the time :)
DO-178B is not only a certification, it is a process that starts the same day as the
development project itself. It will be very hard for an existing application get certified for
any DO-178B level and of course, definitively almost imposible to get Level A certification.