I have never tried a mac.
But anyway the HP Server Recovery Disc is what to use and it is not bootable.
You just insert it and run on the mac.
Then follow the instructions in the screen.
It is desired to have the server directly wired to the mac via Ethernet cable. Bypassing all router, switches,hubs.
Elect Server Recovery or Factory Reset .
It will then prompt you to place the server in recovery mode.
no matter what option you select.
Paper clip in hand. to push in the small hole in the front of the server when you boot it.
This is the hard part. It may take several attempts.
If you have a faulty drive it will always fail.
The full manual is at
http://h10032.www1.hp.com/ctg/Manual/c01868379Follow the directions for Server Recovery and Factory Reset .