This would be dependent on the scripting capabilities of the SIP server. There are several out there. I did something similar years ago with Cisco IPCC and it's scripting environment.
Typically, screen pop is supported where the agent is running the SIP software phone, so the script can run when the agent picks up the call. In the article linked, they have a hardware phone, so yes, you would need to track what IP that agent is logged into their computer in order to send the data to the correct FM client.
Thank you for your reply Mike.
Rats, I forget to often to mark my messages as questions... :-(
When you say SIP server, do you mean the software built into the phone / softphone and it's ability to send different http strings on different triggers?
Regarding the screen popup...
I'm talking about running a script on FM server to trigger another script on a client selected according to the extension number being called to open a FM window containing the appropriate data.
Can this only be done using things like Troi's Activator plugin or can this be done natively in FM?
Or should I be looking at a completely different way to achive something like this?