It should be that simple. The function is only a bios function the OS should not be involved. Only microsoft proprietary sleep crap depends on the OS. Even with no OS the machine should turn on and then drop into the bios screens if it can not find something to actually boot.
There is little you can do on the machine you want to wake. It pretty much turns the option on in the ethernet chip. You should still see the ethernet port light on your switch/router if it has that when this option is set correctly. Some machines the port on the pc itself will leave lights on the ethernet port.
I would run wire shark on the machine you are sending the WOL packet from. Make sure it is the proper format. The packet should be sent to the broadcast mac address and contain the mac of the machine you want to wake in a particular pattern. Wireshark can decode the packet.
Some application attempt to send data to ip addresses which technically is not part of the standard. Some also attempt to send the packet to actual mac of the machine rather than the broadcast. It really depends how strictly the machine you are trying to wake follows the standard. Some take packet formats that they should not really and others will reject packets that for example are not sent to the broadcast address.