Internet---->OpenSBC---->Asterisk---->Class 5 switch

The SBC has two NIC's one public, one private. I have some remote phones that will register, and I can make outbound calls (to the class 5 switch). However inbound calls (Class 5-->Asterisk-->Remote IPT) just hit the asterisk VM. I have OSBC configured the following way:

Assume my public IP is 2.2.2.2 and my Asterisk box is 1.1.1.1

Mode: B2BUpper

RTP Proxy:

Proxy All Media

B2B UA routes

sip:* sip:1.1.1.1:5060

Insert Route Header.

Rewrite-To-URI

B2BUpper routes

sip: * sip:1.1.1.:5060

Re-Write to domain

Any idea what I am missing?