Inbound Route DID Test Failure

Hello All,

Need some help.  This should be easy for most of you to figure out.  Not even sure  if this is the proper place to post this stuff, so if I need to post this somewhere else, please let me know.

I have set up in a lab environment:

-Polycom SoundPoints and VVX's that register to Asterisk/FreePBX on the same private LAN segment. 

-LAN Segment is protected by a SonicWall TZ300. 

-ITSP is on the Internet side of Firewall. 

-PJSIP trunk setup between them whereas the Asterisk/FreePBX registers on the ITSP's Broadworks platform. 

-Outbound calls work fine.

-Inbound calls & routing based on specific CID work fine (now removed)

-Inbound calls work only if I use ANY in the DID field of "Inbound Routes"

What I want to do:

I want to be able to route calls based on DID.  This is very important.  I don't want to set up a SIP trunk for every DID.  I want my ITSP to send calls with various DID's down the Trunk, and I want to route those according to DID.  It's not working. 

Testing:

I spent a lot of time on this yesterday.  I have this narrowed down to 1 of 2 things.  Either the SIP INVITE is being sent to me by the ITSP incorrectly, or Asterisk/FreePBX isn't picking up the DID in the SIP INVITE.   Need some advice here.

Question:

Where does Asterisk/FreePBX pick up DID info when testing for Inbound Routes?  Is it the actual Invite or the "To:" field in the invite?  This is what the invite looks like (165.191.152.108 is Broadworks on Internet.  124.228.42.12 is WAN IP on Firewall NAT'ed to 192.168.168.200.)  :

pjsip show history entry 14

<--- History Entry 14 Received from 165.191.152.108:5060 at 1551583394 --->
INVITE sip:s@124.228.42.12:5060;line=gvpblpv SIP/2.0
Via: SIP/2.0/UDP 165.191.152.108:5060;received=165.191.152.108;branch=z9hG4bKp5gop230fo60321o0660.1
From: "ROHRMAN PETER " <sip:2019615089@165.191.152.5;user=phone>;tag=824350064-1551583394661-
To: "Test Account" <sip:2013804300@stage2.net;line=gvpblpv>
Call-ID: BW222314661020319-1309881562@165.191.152.5
CSeq: 550100403 INVITE
Contact: <sip:2019615089@165.191.152.108:5060;transport=udp>
Allow: ACK, BYE, CANCEL, INFO, INVITE, OPTIONS, PRACK, REFER, NOTIFY
Recv-Info: x-broadworks-client-session-info
Accept: application/btbc-session-info, application/media_control+xml, application/sdp, multipart/mixed
Supported:
Max-Forwards: 59
Content-Type: application/sdp
Content-Disposition: session;handling=required
Content-Length: 242
Content-Type: application/sdp
Content-Length: 242

v=0
o=BroadWorks 1554428664 1 IN IP4 165.191.152.108
s=-
c=IN IP4 165.191.152.108
t=0 0
m=audio 17474 RTP/AVP 0 101
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-15
a=sendrecv
a=ptime:20
a=bsoft: 1 image udptl t38