c++ - QSystemtrayicon: no image on Mac

Question

I've got a problem with the QSystemTrayIcon class on Mac and Linux.

I made a program creating a System tray icon, and I have no problem on Windows, but under Linux (ubuntu 12) and Mac (OSX 10.8), the tray icon is here, but the image on it doesn't show up.

This is what I'm doing in the ctor of my class:

icon = new QIcon("trayIcon.png");
m_pTrayIcon = new QSystemTrayIcon();
m_pTrayIcon->setIcon(*icon);
m_pTrayContextMenu = new QMenu();
m_pTrayContextMenu->addAction(openSettings);
m_pTrayContextMenu->addAction(switchSyncMode);
m_pTrayContextMenu->addAction(openFolder);
m_pTrayContextMenu->addSeparator();
m_pTrayContextMenu->addAction(quit);
m_pTrayIcon->setContextMenu(m_pTrayContextMenu);
m_pTrayIcon->show();

I'm using the Qt 4.8 library.

Anyone have an idea?