I just realized I have another BMessage implementation on my hard drive, and it's not the same Erik wrote. It was written by Marc Flerackers long time ago. I was thinking that if Erik's one turns out to be so much hard to debug (as he doesn't have time to look at it, and I, at least, can't understand anything looking at the code, but I guess it's just because I'm not familiar with template code nor with policies or whatever), we could try Marc's implementation, which is simpler as it doesn't use template code. I can put it online somewhere if someone is interested.