Umm ... the manual is posted there too. Section C (page 84).
Input Voltage: 11.4V - 12.6V.
The operating guide states
For the VIA EPIA TC the AC adapter must run at 12, 5A, and 60W.
It doesn't look too promising for use without regulation and VIA isn't marketing it to be used that way. Basically this board is like the M series board but with a PW70 built in. Without regulation this is probably going to run unreliably and potentially even get damaged.
Do a search around here. There are solutions to build a 12VDC regulator that can be used as an input to this board (or a PW60). A standard laptop car adapter (Radio Shack) would work. Also I believe MikeH is working on a commercial solution that might work also.