AsteriskNOW 1.5 SIP problems

I just loaded the latest AsteriskNOW (1.5) iso onto a fresh computer, completely replacing whatever was on the HardDrive.

FreePBX version 2.5.1
Centos 5.3
Dell GX280, w 1.5gb ram, 500gb hd

First problem was no SIP commands in the console. I upgraded the Core and related items, and after reboot, now SIP commands are in Console.

(I then added a sip provider tunk.)
However, it does not register with VOIP provider.
Console says
’Got SIP response 400 “Bad Request” back from (ip addr)'
It repeats this every 10 seconds or so.

The sip register message comes back with
"Contact parse error"

REGISTER 13 headers, 0 lines
Reliably Transmitting (no NAT) to (VP ip):5060:
REGISTER sip:(VP name) SIP/2.0
Via: SIP/2.0/UDP;branch=z9hG4bK46236d44;rport
From: <sip:(my acct)@(vp name).com>;tag=as0806ef9d
To: <sip:(my acct)@(>
Call-ID: [email protected]
User-Agent: Asterisk PBX
Max-Forwards: 70
Authorization: Digest username="(my acct)", realm="(vp name .com)", algorithm=MD5, uri=“sip:(vp name)”, nonce=“4a8ed2c50000192ba7c967e8ec071e4e037c29a64223c30e”, response="95350920e03eab930535d962fc96f9b2"
Expires: 120
Contact: sip:[email protected]
Event: registration
Content-Length: 0

By setting up sip_nat.conf, the problem solved. Because I am behind a nat router. Somehow I must have missed that in the docs.