Comment 1 for bug 693855

I am going to assume you use grub2 currently, right? Burg makes use of the grub2 configuration settings... While I do not have a solution to your problem, I may have a work-around: (though I am not an Arch-Linux user, and am not familiar with BSD)
1. Try installing a package called Grub Customizer.
     1.a. It maybe easier to do from an ubuntu live session, since they have a ppa, which can be added by typing | sudo add-apt- repository ppa:danielrichter2007/grub-customizer && apt-get install grub customizer | into the terminal.
     1.b. Although, you should definitely try to compile from source and add Grub Customizer to your arch-linux install!
2. Once that is done, load grub customizer and see if it says "Burg Found! Do you want to configure BURG instead of GRUB2?" Select | Yes.|
3. You may find that this program will detect your OS's better than Burg-Prober, you may not. Either-way, this is a program you will want if you want to customize your boot-manager.