QML:
    function saveConnection()
    {
        var _name = conname.text;
        var _gateway = gateway.text;
        var _conntype = connectionType.currentItem;
        if(_conntype.toString() === "X.509 Certificates")
            _conntype = ConnectionType.X509;
        var _cafile = caFile.text;
        var _certfile = certFile.text;
        var _keyfile = keyFile.text;

        var _port = port.text;
        if(_port === "")
            _port = -1;

        var _mtu = mtu.text;
        if(_mtu === "")
            _mtu = -1;

        var _prototype = protocol.currentItem;
        if(_prototype.toString() === "UDP")
            _prototype = ProtocolType.UDP;
        else if(_prototype.toString() === "TCP")
            _prototype = ProtocolType.TCP;

        var _lzo = complzo.checked;

        //ConnectionsModel.newConnection(_name, _gateway, _conntype,
        //                               _cafile, _certfile, _keyfile,
        //                               _port, _mtu, _prototype, _lzo);
        ConnectionsModel.newConnection("_name", "_gateway", 0,
                                       "_cafile", "_certfile", "_keyfile");
    }

CPP:
QString ConnectionsModel::newConnection(const QString &name, const QString &gateway, const ConnectionTypeWrapper::ConnectionType &conntype,
                                        const QString &cafile, const QString &certfile, const QString &keyfile, const qint32 &port,
                                        const qint32 &mtu, const ProtocolTypeWrapper::ProtocolType &prototype, const bool &lzo)
{
    Connection *conn = new Connection(name, gateway, conntype,
                    cafile, certfile, keyfile, port,
                    mtu, prototype, lzo);

    qint32 index;
    if(m_conns.isEmpty())
        index = 0;
    else
        index = m_conns.length();
    conn->setIndex(index);
    addConnection(conn);

    return "";
}

ERROR GDB:
[W] unknown:68 - file:///usr/share/OpenVPN/qml/pages/Settings.qml:68: Error: Unable to determine callable overload.  Candidates are:
    newConnection(QString,QString,ConnectionTypeWrapper::ConnectionType,QString,QString,QString)
    newConnection(QString,QString,ConnectionTypeWrapper::ConnectionType,QString,QString,QString,int)
    newConnection(QString,QString,ConnectionTypeWrapper::ConnectionType,QString,QString,QString,int,int)
    newConnection(QString,QString,ConnectionTypeWrapper::ConnectionType,QString,QString,QString,int,int,ProtocolTypeWrapper::ProtocolType)
    newConnection(QString,QString,ConnectionTypeWrapper::ConnectionType,QString,QString,QString,int,int,ProtocolTypeWrapper::ProtocolType,bool)