I think you have answered your own question but, a word of caution. Your Belgian National PPL will cease to exist after April 2012 when EASA FCL comes into force. You will then have to obtain an EASA licence. Any FAA Certificate obtained on the back of your Belgian Licence will no longer be valid so I suggest you convert to a JAA licence first, then obtain your FAA Restricted Certificate which unfortunately will require a short trip to the USA as well as a validation from the Belgian DGAC.