I would like to create a tool that has a mirror at its end.
Following the example 23-tooth I created a secondary camera and attached it to my mirror tool.
Then I created a frameBuffer but I don't want to use it in a cViewPanel like in the example.

    // attach mirror to tool
    tool->m_image->addChild(mirror);

    // create secondary camera for side view
    cCamera* cameraTool = new cCamera(world);

    // attach camera to tool
    mirror->addChild(cameraTool);
    cameraTool->setLocalPos(0.0, 0.0, 0.1); 

    // create framebuffer for side view
    frameBuffer = cFrameBuffer::create();
    frameBuffer->setup(cameraTool);

mirror->m_texture->setImage((cImagePtr)frameBuffer);

You can create a mirror by using a cMesh object and by assigning the texture to the framebuffer:

    // create mirror
    cMesh* mirror = new cMesh();

    // add mirror to world
    world->addChild(mirror);

    // create disc
    cCreateDisk(mirror, 0.2, 0.2);

    // assign framebuffer texture
    mirror->setTexture(frameBuffer->m_imageBuffer);

    // enable texture rendering
    mirror->setUseTexture(true);

    // disable material properties
    mirror->setUseMaterial(false);

    // render framebuffer
    frameBuffer->renderView();

    // render world
    camera->renderView(windowW, windowH);

That's what I needed :

// assign framebuffer 
texturemirror->setTexture(frameBuffer->m_imageBuffer);

I want to create an object with mirror at the end, too. But my device is custom device with non-actuated rotation.

When I add a camera to the tool image and render the frame buffer, I get a picture from another viewpoint which I don't know the logic of its place and for some small time I get frames from the real position of the camera. In other words I get some blinks from real position of camera.

Anybody knows what the problem is?

You will have update the orientation of the camera on the mirror according to the position of the camera rendering the full scene so that the reflection angle is consistent.

Regarding the device orientation, does your device support orientations? From you message its sounds like your device support 3-DOF in translation.