Asterisk not registering to SIP trunk, and phones not taking calls 2.6 rc2

I am using 2.6 RC2/asterisk1.4.21/zap, and am trying to migrate from an old Asterisk 1.2 system (non freepbx), which worked completely on the same network with the same phones and same trunks. My build template is also used on several other systems without a fault.
I built my trunks and everything in Freepbx, but it appears that asterisk is not reading the includes properly because my sip registration was not showing up under 'sip show registry' - its empty.
Besides that I added some NAT settings to sip_general_custom.conf under [general], and when running sip debug on my trunk peer it showed 192.168 addresses, I added these settings directly to sip.conf and then it showed the correct NAT IPs in sip debug.
I then added the sip registration directly to sip.conf and 'sip show registry' showed trunks registered, however at this point my extensions would only ring once (at the extension), then go to voicemail.
At this point, I went in and hit submit on some extensions, no change, so I started from fresh asterisk/zap/freepbx source and compiled it again, now nothing works, no registrations show up, no phones work.
Original Ast 1.2 SIP.CONF:
[general] bindport=5060 bindaddr=0.0.0.0 context=invalid-context musicclass=default externip=173.160.133.52 localnet=192.168.102.0/255.255.255.0 nat=yes allowguest=no useragent=PBXware maxexpirey=7200 defaultexpirey=3600 realm=PBXware progressinband=never disallow=all allow=ulaw allow=alaw register => 1166:LCHezOuK@66.5.5.5:5060 [2800_in] type=friend dtmfmode=rfc2833 context=2800_in canreinvite=no qualify=8000 host=66.5.5.5 username=1166 secret=LCHezOuK disallow=all allow=ulaw allow=alaw insecure=very deny=0.0.0.0/0.0.0.0 permit=175.166.184.171
Trunks as entered in FreePBX:
Trunk Name: 2800_in Peer Details: type=friend dtmfmode=rfc2833 context=from-trunk canreinvite=no qualify=yes host=66.5.5.5 username=1166 secret=LCHezOuK disallow=all allow=ulaw&alaw insecure=very registration: 1166:LCHasdfsduK@66.5.5.5:5060
Some debug:
Reliably Transmitting (NAT) to 66.5.5.5:5060: OPTIONS sip:66.5.5.5 SIP/2.0 Via: SIP/2.0/UDP 174.16.133.53:5060;branch=z9hG4bK33595b2b;rport From: "asterisk" <sip:asterisk@174.16.133.53>;tag=as298629cd To: <sip:66.5.5.5> Contact: <sip:asterisk@174.16.133.53> Call-ID: 00b0d20a2780589656d021e952da5b0c@174.16.133.53 CSeq: 102 OPTIONS User-Agent: PBXware Max-Forwards: 70 Date: Thu, 15 Oct 2009 19:42:18 GMT Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Supported: replaces Content-Length: 0 <--- SIP read from 66.5.5.5:5060 ---> SIP/2.0 404 Not Found Via: SIP/2.0/UDP 174.16.133.53:5060;branch=z9hG4bK33595b2b;rport;received=174.16.133.53 From: "asterisk" <sip:asterisk@174.16.133.53>;tag=as298629cd To: <sip:66.5.5.5>;tag=as5c1e1069 Call-ID: 00b0d20a2780589656d021e952da5b0c@174.16.133.53 CSeq: 102 OPTIONS User-Agent: Telcoware Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, SUBSCRIBE, NOTIFY Accept: application/sdp Content-Length: 0 [2009-10-14 23:28:06] DEBUG[8631] chan_sip.c: Adding subscription for extension 2801 context from-internal for peer 2801 [2009-10-14 23:28:06] VERBOSE[8631] logger.c: -- Incoming call: Got SIP response 400 "Bad Request" back from 192.168.102.250


