Looking at the Festool worldwide site and noticed they offer a fiber cutting blade. Just wondering why it isn't offered here in the states? Last time I checked especially here in the south. Fiber board and hardy board is rather popular and easily available.
http://www.festool.com/EN/Products/Accessories/Pages/Detail.aspx?pid=435450&name=Special-saw-blade-170x2-0x30-TF56
http://www.festool.com/EN/Products/Accessories/Pages/Detail.aspx?pid=435450&name=Special-saw-blade-170x2-0x30-TF56