I connected M1 cables and tried to automatically wake up my PC but it doesn't

when i disconnect power switch cables from M1 and switch power manually then my PC wakes up and works perfectly. I have read trough troubleshooting section, doublechecked all cables and connections and tried again, but no luck

switching again manually, pc comes up.
Tried same M1 on VIA miniITX mobo, there it worked as it must. But M1 doesn't wake up my aOpen i855GMEe-LFS Pentium M mobo
Any suggestions, what to try what to do to get automatic powerswitch working?