WebDriver driver = new FirefoxDriver();
Selenium selenium = new WebDriverBackedSelenium(driver, "http://mysite.com");
RenderedWebElement element = (RenderedWebElement) driver.findElement(By.className("batchMenuClass"));

// We can't figure out how to get this to work.  Instead, we have to repeat the same selector logic on both the WebDriver and Selenium side
selenium.fireEvent(element, "mouseover");

// This is the strategy we've had to resort to so far
selenium.fireEvent("css=.batchMenuClass", "mouseover");