[SR-Users] Question about Presence Federation and Interacting with the Kamailio 4.x Presence Module

Hello sr mailing list, I've been banging my head around this for a while. I have an interesting use case. We have a remote site where the user's SIP phones register to a MetaSwitch Call Feature Server. This CFS supports all the presence RFCs like RFC 4235 (Dialog Event Package) and RFC 3856 (Presence Event Package). Those users also have a GUI on their desk PC's that provide the user with information about the state our our application. Now the use case, I want to have the "presence" state of the SIP phones (on-hook/Open, off-hook/InUse) displayed on the GUI. I already have the communication channel between the backend application server and the GUI. What I need guidance on is, 1. Is it possible to setup my Kamailio (4.0.3/CentOS 6.4 32 bit) to receive PUBLISH messages from the MetaSwitch CFS which is responsible for the Presentities under its control. I'm optimistic that this may be a simple SIP Trunk. 2. My application server (which would act as the Watcher) will need to subscribe to the presence events of a list of presentities I'm interested in. This could be done by using SIP and sending a SUBSCRIBE message, but my application doesn't have a SIP stack so is there a API to interact with the Presence module? 3. As per the RFCs and documentation the "watcher application" is responsible for consuming the NOTIFY messages. Once again my application doesn't have a SIP stack so is there a API that my application can poll for or can listen for presence event updates at a higher layer than SIP/SIMPLE Any guidance would be appreciated. Regards, Tony de Sousa