If you don't have apm or acpi in the kernel, it won't power the monitor off. That is not a bug. You just need to put the option in the kernel. I use apm, because it works for me, some use acpi because their rig likes it. Try one, if it works for you, use it. If it don't, try the other.
You also may want to check the bootloader. Sometimes they disable the option there as well.
Later