The following template checks whether the group notification works. In order to use it, change the parameters within the configuration section and place the script inside a primitive in-world. The template should indicate that the group notification has been installed, after which talking in group chat should make the template print out the notification data on local chat.

///////////////////////////////////////////////////////////////////////////
//  Copyright (C) Wizardry and Steamworks 2013 - License: CC BY 2.0      //
///////////////////////////////////////////////////////////////////////////
 
///////////////////////////////////////////////////////////////////////////
//                            CONFIGURATION                              //
///////////////////////////////////////////////////////////////////////////
// The UUID / Key of the scripted agent.
string CORRADE = "";
// The name of the group to invite to.
string GROUP = "";
// The password for that group in Corrade.ini.
string PASSWORD = "";
 
/////////////////////////////////////////////////////////////////////////// 
//                        END CONFIGURATION                            //
///////////////////////////////////////////////////////////////////////////
 
///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2013 Wizardry and Steamworks - License: CC BY 2.0    //
///////////////////////////////////////////////////////////////////////////
string wasKeyValueEncode(list kvp) {
    if(llGetListLength(kvp) < 2) return "";
    string k = llList2String(kvp, 0);
    kvp = llDeleteSubList(kvp, 0, 0);
    string v = llList2String(kvp, 0);
    kvp = llDeleteSubList(kvp, 0, 0);
    if(llGetListLength(kvp) < 2) return k + "=" + v;
    return k + "=" + v + "&" + wasKeyValueEncode(kvp);
}
 
///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2015 Wizardry and Steamworks - License: CC BY 2.0    //
///////////////////////////////////////////////////////////////////////////
// escapes a string in conformance with RFC1738
string wasURLEscape(string i) {
    string o = "";
    do {
        string c = llGetSubString(i, 0, 0);
        i = llDeleteSubString(i, 0, 0);
        if(c == "") jump continue;
        if(c == " ") {
            o += "+";
            jump continue;
        }
        if(c == "\n") {
            o += "%0D" + llEscapeURL(c);
            jump continue;
        }
        o += llEscapeURL(c);
@continue;
    } while(i != "");
    return o;
}
 
///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2015 Wizardry and Steamworks - License: CC BY 2.0    //
///////////////////////////////////////////////////////////////////////////
// unescapes a string in conformance with RFC1738
string wasURLUnescape(string i) {
    return llUnescapeURL(
        llDumpList2String(
            llParseString2List(
                llDumpList2String(
                    llParseString2List(
                        i, 
                        ["+"], 
                        []
                    ), 
                    " "
                ), 
                ["%0D%0A"], 
                []
            ), 
            "\n"
        )
    );
}
 
///////////////////////////////////////////////////////////////////////////
//    Copyright (C) 2015 Wizardry and Steamworks - License: CC BY 2.0    //
///////////////////////////////////////////////////////////////////////////
string wasListToCSV(list l) {
    list v = [];
    do {
        string a = llDumpList2String(
            llParseStringKeepNulls(
                llList2String(
                    l, 
                    0
                ), 
                ["\""], 
                []
            ),
            "\"\""
        );
        if(llParseStringKeepNulls(
            a, 
            [" ", ",", "\n", "\""], []
            ) != 
            (list) a
        ) a = "\"" + a + "\"";
        v += a;
        l = llDeleteSubList(l, 0, 0);
    } while(l != []);
    return llDumpList2String(v, ",");
}
 
string URL = "";
 
default {
    state_entry() {
        llRequestURL();
    }
    http_request(key id, string method, string body) {
        if(method != URL_REQUEST_GRANTED) return;
        URL = body;
        state main;
    }
}
 
state main {
    state_entry() {
        llInstantMessage(CORRADE,
            wasKeyValueEncode(
                [
                    "command", "notify",
                    "group", wasURLEscape(GROUP),
                    "password", wasURLEscape(PASSWORD),
                    "action", "set",
                    "type", wasListToCSV([
                        "group"
                    ]),
                    "URL", wasURLEscape(URL),
                    "callback", wasURLEscape(URL)
                ]
            )
        );
 
        llOwnerSay("sent...");
    }
    http_request(key id, string method, string body) {
        llHTTPResponse(id, 200, "Ok");
        llOwnerSay(wasURLUnescape(body));
    }
}