Hi Leandro,  if your JUnit Selenium testcase is taking screenshots and you want to attach them to the execution result you can do this by writing the screenshot file to the directory specified by the Java System property named "selenium.screenshot.dir".  After each JUnit test is executed this directory is scanned for new image files and any found are attached to the execution result and associated with the corresponding test.  You could create a small method like the following to do this.

    private void takeScreenShot(String fname) throws Exception {
        File scrFile = ((TakesScreenshot)driver).getScreenshotAs(OutputType.FILE);
        String imageFileDir = System.getProperty("selenium.screenshot.dir");
        if (imageFileDir == null)
            imageFileDir = System.getProperty("java.io.tmpdir");
        FileUtils.copyFile(scrFile, new File(imageFileDir, fname));
    }

The details about selenium.screenshot.dir missed getting into the RQM 4.0 documentation but should be present in the 4.0.0.1 version of the docs.

Note that the adapter will only look for image files, ie. files with the following suffixes, .png, .jpg, .jpeg, .gif, .tif, .bmp.  Be sure the names you specify include one of these.