First things first,
1. Do you have a SIP route built in the CS1000?
2. Do you have an RLI referencing the SIP route in LD 86?
3. Do you have your CS1000 Configured as a SIP endpoint in NRS?
4. Do you have a Node ID built and working?
5. Do you have licensing in your CS1000 for SIP Access Ports?
6. Do you have the Asterisk PBX configured as a Static SIP endpoint in NRS?
7. Do you have Routing Entries configured in your NRS for your Asterisk PBX?
8. Do you have CDP, DSC entries in LD 87 referencing the DNs your Asterisk PBX is using?
9. Do you have a DNS entry that matches your NRS's IP to the Service Domain defined in NRS?
Once you can answer yes to all that, the Nortel side of your configuration is done.
Let me know when you have all that done. I will not offer much help in the configuration of each of those tasks above as they are very time consuming to explain, plus all of those tasks have been answered in some form in forums across the internet. Most of them here.
