Right, with apm disabled acpi should take over.. you never showed a dmesg with acpi enabled yet, so, can't we work with that.
If apm is at fault for some reason, you could try version 1.1 instead of 1.2.
Originally Posted by apm(4)
The driver supports versions 1.0, 1.1, and 1.2 interface specifications.
The value of 0x0101 would specify version 1.1 of the interface specification to be used.
This can be set via config(8) or boot time UKC, sadly this all is really hit and miss.. sometimes vendors just don't entirely comply with standards.
ukc> change apm
321 apm0 at bios0 disable flags 0x0
change [n] y
flags  ? 0x0101
321 apm0 changed
321 apm0 at bios0 disable flags 0x101