[Serusers] B2BUA and NAT.

Hi. I can't find enough info regarding B2BUA, and how it works. At least I know that it is not scalling and it breaks SIP peer2peer functionality. BUT, it is said that it can handle NAT, HOW? 1.Does it solve NAT because it stays in the middle and proxy everything (+ media) or 2.can it be involved in the call only when NAT is detected like rtp proxy ? 3. iF 2, THEN how does it work in corporation with SER or any SIP Server? 4. Which situation will rtp proxy (rtpproxy/mediaproxy) fail to solve NAT issues NB. I just need to expand my knowledge regarding options. I'm using rtpproxy, it works fine in every respect only if I start it in foreground Regards.