I appreciate that this is frustrating, but you have two choices whenever deploying any form of solution- pay for it or learn how to do it yourself. all your questions are answerable by googling generally and searching this forum specifically. If you are unable/unwilling to research and give up, I doubt anyone here will be offended.
IF you want to boot from a hardware raid volume, you have to specify it as the booting lun in your controller bios. you can start here:
http://h10032.www1.hp.com/ctg/Manual/c02289065.pdf
IF you want to boom from a zfs lun and are getting stuck in grub, you may wish to consult the Proxmox documentation, which is pretty good- have a look here:
https://pve.proxmox.com/wiki/ZFS:_Tips_and_Tricks#Grub_boot_ZFS_problem