Android-based phones (also iPad, etc.) are working properly (both internally and externally) but this "Windows-based" phones are not (both internally and externally). After many troubleshooting that I did, this is what I've observed: Windows-based mobile phones are only working on "HTTP (port 80)" based connection, not "https (port 443)" connection. I've defined the URL of the Lync Server on the Lync for Mobile connection setttings on the Windows-based mobile phone. Again, do not use "https (port 443)", instead use the "http" (port 80). Don't forget to properly configure your Lync 2010. In this scenario I'm not using a TMG/ISA Server, fyi.
