GA-7N400E system and power fans monitoring issue

I have build PC for my friend. The mainboard is GA-7N400E with newest
bios available on the Gigabyte web site (F5). OS is Win XP Pro with
all the up to date service packs and critical updates. Everything
works just fine except one issue: I have attached 2 fans - cpu fan
(obviously) and system fan, both Coolermaster brand and both are
spinning which I can see when I open the case or when I check PC
Health Status section in bios (both are shown with RPM numbers > 0).
Unfortunately in Hardware Monitoring tab in EasyTune4 (
http://tw.giga-byte.com/MotherBoard/FileList/NewTech/tech_hw_monitor.htm
), there is no system fan listed and there is power1 fan with 0 RPM. I
have studied user's manual and motherboard itself very carefully, but
I couldn't find power fan connector. I also installed Gigabyte
hardware health Utility that comes from my own GA-7VAXP bundle and is
working with this particular motherboard perfectly, but in the
GA-7N400E system it behaves exactly the same as EasyTune4. I also
connected 2 different fans to the system fan connector, but both
weren't seen by EasyTune4 nor Gigabyte hardware health Utility.
Instead of monitoring system fan both programs keep on trying to
monitor power fan that is impossible to connect.
I wonder how to force any of those two applications to proper fan
monitoring? What could be the cause? Could it be serious I mean
motherboard hardware defect?
Thanks in advance for your help. Regards. Mr-B.
Pozdrawiam,
Mr-B