Lenovo does not typically release a standalone "motherboard manual" for OEM boards like the IS7XM. Instead, technical details are contained within the for the systems that house them.
This is the most requested part of the "manual." The front panel header (F_PANEL) on the IS7XM Rev 1.0 is non-standard compared to retail motherboards. lenovo is7xm rev 1.0 motherboard manual