project:OpenSim.Grid.UserServer
file:UserManager.cs

using System;
using System.Collections;
using Nwc.XmlRpc;
using OpenSim.Framework.Data;
using OpenSim.Framework.UserManagement;
using OpenSim.Framework.Utilities;

namespace OpenSim.Grid.UserServer
{
    public class UserManager : UserManagerBase
    {
        public UserManager()
        {
        }

        /// <summary>
        /// Customises the login response and fills in missing values.
        /// </summary>
        /// <param name="response">The existing response</param>
        /// <param name="theUser">The user profile</param>
        public override void CustomiseResponse(  LoginResponse response,   UserProfileData theUser)
        {
            // Load information from the gridserver
            SimProfileData SimInfo = new SimProfileData();
            SimInfo = SimInfo.RequestSimProfileData(theUser.currentAgent.currentHandle, _config.GridServerURL, _config.GridSendKey, _config.GridRecvKey);

            // Customise the response
            // Home Location
            response.Home = "{'region_handle':[r" + (SimInfo.regionLocX * 256).ToString() + ",r" + (SimInfo.regionLocY * 256).ToString() + "], " +
                "'position':[r" + theUser.homeLocation.X.ToString() + ",r" + theUser.homeLocation.Y.ToString() + ",r" + theUser.homeLocation.Z.ToString() + "], " +
                "'look_at':[r" + theUser.homeLocation.X.ToString() + ",r" + theUser.homeLocation.Y.ToString() + ",r" + theUser.homeLocation.Z.ToString() + "]}";

            // Destination
            Console.WriteLine("CUSTOMISERESPONSE: Region X: " + SimInfo.regionLocX + "; Region Y: " + SimInfo.regionLocY);
            response.SimAddress = SimInfo.serverIP;
            response.SimPort = (Int32)SimInfo.serverPort;
            response.RegionX = SimInfo.regionLocX;
            response.RegionY = SimInfo.regionLocX;

            //<add>
            //Not sure if the + "/CAPS/" should in fact be +"CAPS/" depending if there is already a / as part of httpServerURI
            string capsPath = Util.GetRandomCapsPath();
            response.SeedCapability = "http://" + SimInfo.httpServerURI + "/CAPS/" + capsPath + "0000/";
            //</add>

            // Notify the target of an incoming user
            Console.WriteLine("Notifying " + SimInfo.regionName + " (" + SimInfo.serverURI+ ")");
            
            // Prepare notification
            Hashtable SimParams = new Hashtable();
            SimParams["session_id"] = theUser.currentAgent.sessionID.ToString();
            SimParams["secure_session_id"] = theUser.currentAgent.secureSessionID.ToString();
            SimParams["firstname"] = theUser.username;
            SimParams["lastname"] = theUser.surname;
            SimParams["agent_id"] = theUser.UUID.ToString();
            SimParams["circuit_code"] = (Int32)Convert.ToUInt32(response.CircuitCode);
            SimParams["startpos_x"] = theUser.currentAgent.currentPos.X.ToString();
            SimParams["startpos_y"] = theUser.currentAgent.currentPos.Y.ToString();
            SimParams["startpos_z"] = theUser.currentAgent.currentPos.Z.ToString();
            SimParams["regionhandle"] = theUser.currentAgent.currentHandle.ToString();
            
            //<add>
            SimParams["caps_path"] = capsPath;
            //</add>

            ArrayList SendParams = new ArrayList();
            SendParams.Add(SimParams);

            // Update agent with target sim
            theUser.currentAgent.currentRegion = SimInfo.UUID;
            theUser.currentAgent.currentHandle = SimInfo.regionHandle;

            System.Console.WriteLine("sending reply");
            // Send
            XmlRpcRequest GridReq = new XmlRpcRequest("expect_user", SendParams);
            XmlRpcResponse GridResp = GridReq.Send(SimInfo.httpServerURI, 3000);
        }
    }
}

Project:OpenSim.Region.Communications.OGS1
file:OGS1GridServices.cs

 // Grid Request Processing
        /// <summary>
        /// 
        /// </summary>
        /// <param name="request"></param>
        /// <returns></returns>
        public XmlRpcResponse ExpectUser(XmlRpcRequest request)
        {
            Console.WriteLine("Expecting User...");
            Hashtable requestData = (Hashtable)request.Params[0];
            AgentCircuitData agentData = new AgentCircuitData();
            agentData.SessionID = new LLUUID((string)requestData["session_id"]);
            agentData.SecureSessionID = new LLUUID((string)requestData["secure_session_id"]);
            agentData.firstname = (string)requestData["firstname"];
            agentData.lastname = (string)requestData["lastname"];
            agentData.AgentID = new LLUUID((string)requestData["agent_id"]);
            agentData.circuitcode = Convert.ToUInt32(requestData["circuit_code"]);

            //<add>
            agentData.CapsPath = (string)requestData["caps_path"];
            //</add>

            if (requestData.ContainsKey("child_agent") && requestData["child_agent"].Equals("1"))
            {
                agentData.child = true;
            }
            else
            {
                agentData.startpos = new LLVector3(Convert.ToUInt32(requestData["startpos_x"]), Convert.ToUInt32(requestData["startpos_y"]), Convert.ToUInt32(requestData["startpos_z"]));
                agentData.child = false;

            }

            if (listeners.ContainsKey(Convert.ToUInt64((string)requestData["regionhandle"])))
            {
                this.listeners[Convert.ToUInt64((string)requestData["regionhandle"])].TriggerExpectUser(Convert.ToUInt64((string)requestData["regionhandle"]), agentData);
            }
            else
            {
                MainLog.Instance.Error("ExpectUser() - Unknown region " + ((ulong)requestData["regionhandle"]).ToString());
            }

            MainLog.Instance.Verbose("ExpectUser() - Welcoming new user...");

            return new XmlRpcResponse();
        }