This field will most probably stay in the domain of fixed target experiments since not enough energy is available in the decay of a B-meson (the minimal decay chain would be B ). The observation power is directly related to the total number of charm events observable. Baryon beams may have an advantage over or beams. The use of a hyperon beam by E781 probably gives no advantage over the use of a proton beam. However, the beam energy could be of importance (E781 has 600 GeV/c as compared to 280 GeV/c for COMPASS in its first stage). Since COMPASS aims at 10 times higher statistics as compared to E781 and the projected yields are of the order of 50-500 reconstructed events, it seems unlikely that E781 could study these objects first. Even if a first observation were done by E781 (which would imply a relatively high production cross section) this would in turn imply a richer physics program in this field for COMPASS. In addition the COMPASS target detector should be better suited to disentangle complex event topologies.