BrowserFactory on OSX

I wrote a plugin for spark which opens a browser window using BrowserFactory BrowserFactory.getBrowser()

This appears to only work on windows and not macosx? Anyone have any suggestions? I want to be able to open a window that can load a URL.

It looks to me as though the current code assumes that all non-windows platforms have Mozilla installed

if (Spark.isWindows()) {
            bem.setActiveEngine(BrowserEngineManager.IE);
        }
        else {
            bem.setActiveEngine(BrowserEngineManager.MOZILLA);
        }