Typical Eurocontrol/JAA wording!!! Of course you can allow a non-RVSM aircraft into RVSM airspace - it's just that you might want to use 5000ft vertical separation....
Well, they're only talking about the ICAO RVSM requirements (general I guess) and for Europe there's the D7030 for example, which clearly states that in case if an aircraft is non-RVSM and not state approved it cannot enter to the RVSM airspace.