cmd = new Strophe.Commands.RemoteCommand(conn, jid, node);

cmd.execute({

  success: function(res, cmd){

    proccessFields( cmd.form.fields );
    doSomething();
    resp = new Strophe.x.Form();
    cmd.complete({ responseForm: resp });

  error: myErrorFunction

}});

cmd.execute({gui:true});

conn.cmds.add({node: "nodename", name: "Command description"},
    function(request, result) {
        var command_successful = doSomething(request);

        result.attrs({status: "completed"});

        if (command_successful) {
            result.c('note', {type: "info"}, 'infotext');
        } else {
            result.c('note', {type: "info"}, 'infotext');
            result.c('error', {type: 'cancel'});
            result.c('forbidden', {xmlns: 'urn:ietf:params:xml:ns:xmpp-stanzas'});
        }
        return result;
});