I guess you either have to create a seperate wake-up task or create a Provisioning Distribution Package and schedule that. That way you have all task options available, including the wake up devices option.
a few months ago I had a ticket open about exactly this issue. I was told "the WOL option has been relocated to make it easier to locate with the new layout of task properties". I should make a batch and deploy the batch with the WOL function. I think sooner or later these scripts will die and all is moved to distribution packages. Just my thoughts...