Does Asterisk actually support two NATs?

Hello

Since I'm not making any progress... I'd like confirmation that Asterisk does indeed support two NATs, one on either side:

img86.imageshack.us/img86/2946/twonatsmk0.jpg

Using this setup, phones do ring… but there’s no voice in either direction, even when not relying on STUN and opening SIP and RTP ports statically on the two NAT + switch routers.

=> Does someone successfully use Asterisk in one network behind a NAT router, and calls into it from a remote IP phone behind its own NAT router?

Thank you.