Please correct me if I'm wrong, but I think you currently have an analogue device such as a auto dial, modem or fax machine etc that currently works via an ATA adapter that is connected to a M2616 digital phone via it's data port using Remote Office?.
If that is the case, then I fully understand the problem you have in trying to get it to work once the ISDN link from the CS1000 to the Remote Office has been ceased.
I'm guessing that you only have the 1220 sets deployed?. You mentioned that you don't have any SIP licenses and does this apply to both IP phones and trunks?.
The reason for my asking is that I had a problem along the same lines a couple of years ago where I had a BCM 50 system and I wanted to add in the SIP trunks, but didn't have any SIP trunk licenses at that time. I only have two analogue trunks to use.
What I did was to get off eBay a Cisco Linksys 2 port VOIP adapter that a colleague recommended which was pretty cheap at just under £18.
This device was easy to set up and it supports a variety of protocols and allowed me to try out SIP trunks via the analogue trunks on the BCM 50. The Linksys has two RJ11 ports to connect up an analogue device.
I've found an example below for you.
However, it will only support SIP trunks.
Because of this, there is another solution that might be feasible for you which is to go to a SIP trunk provider and have a service from them to use with the adapter as you must already have an internet service at that location.
In the UK, I use a provider that allows SIP calls between their own customers for free. I also have another account in the States that offers the same thing.
This way, you won't have to pay for an analogue line to be fitted and also no monthly line rental.
I found the quality of the Linksys adapter to be perfect.
Another way, could be to have an SRG system such as a BCM 50 fitted with the analogue ports enabled. These systems can be obtained very cheaply and for some of us, keycodes are no longer a major headache.
Firebird Scrambler
Nortel and Avaya Meridian 1 / Succession and BCM / Norstar Programmer in the UK
Very advance high level knowledge on Linux BCM with keycode support