I don't understand why you don't get the correct CID. Like I said, mine works.
Anyway, you can try the following.
Get a free Sip2Sip account here:
https://mdns.sipthor.net/register_sip_account.phtmlOn OBi2 register one of the SP trunks to your Sip2Sip account.
Service Provider -> ITSP Profile A or B -> SIP
ProxyServer:
sip2sip.infoX_DnsSrvAutoPrefix: Enabled (checked)
Voice Services -> SP1/2 Service
AuthUserName: YourSip2SipID
AuthPassword: YourSip2SipPassword
On OBi1
Change Line Port -> InboundCallRoute to:
{ph,sp2(YourSip2SipID@sip2sip.info.com;ui=$1)}