Letter dated 2004/04/23 from the Permanent Representative of the Netherlands to the Conference on Disarmament addressed to the Secretary-General of the Conference on Disarmament transmitting a summary of the 6th open-ended informal meeting in the framework of the Netherlands' FMCT-Exercise, on a treaty banning the production of fissile material for nuclear weapons and other nuclear explosive devices, held in Geneva on 2 April 2004