Possible ACPI shutdown/power off issue

[Steve]

I'm using 6.2-R on a Dell PowerEdge 400SC.

I recently enabled "Remote Wake Up" (Wake on LAN) in BIOS.  Sending a
magic packet to the powered down PC will power it up and it boots
normally.  However, now if I attempt a shutdown and power off using
commands "halt -p" or "shutdown -p now" I get a reboot.  Disabling WOL
reverts back to the expected behavior.

I've searched and found the sysctl knob "hw.acpi.disable_on_poweroff"
as a possible solution, but sysctl gives me "unknown oid".

I'm guessing this issue is related to ACPI.  I'm puzzled why enabling
WOL would have this impact.  Any ideas on how to fix or troubleshoot
this?  Thank you.

Steve