C++:

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->quickViewA->setSource(QUrl::fromLocalFile("a.qml"));
    ui->quickViewB->setSource(QUrl::fromLocalFile("b.qml"));

    //QML connect
    //try 1
    connect(  ui->quickViewA, SIGNAL( foo(  QVariant )),  ui->quickViewB, SLOT( foo( QVariant )));
    //try 2
    connect(  ui->quickViewA, SIGNAL( foo(  int )),  ui->quickViewB, SLOT( foo( int )));
}

MainWindow::~MainWindow()
{
    delete ui;
}

a.qml:

import QtQuick 2.4

Rectangle { 
	id: root
	signal foo(int id)
	MouseArea {
		anchors.fill: parent
		onClicked: { 
			root.foo(42)
		}
	}
	color:"red"
}

b.qml:

import QtQuick 2.4

Rectangle { 
	function foo(id){ console.log(id) }
}

In both cases it can't find the signal.
I am doing something wrong or is it just not possible to do it this way?