First of all thank you for the support. I am not an expert in UE, and coming from the Max/MSP world, thanks to Metasounds, and my production experience in Immersive Sound, I am literally enjoying learning and making mistakes with this amazing environment. Said this, I can confirm (at least with this experience) that the issue is related to BPI and triggering Play in MS contained in BPs. Values change, what really does not work is the File selection mechanism as described above (BP public variable integer->MS input int32->Assets array->Wave Player) EDIT-> all other variables do work (like Frequency change, Bar/Tempo changes, etc.). This scheme (Changing File via Public variable->etc.) works instead if the BP is activated directly with its own collision box.