I finally solved my issue by using ShadowProtect. I backed up the System Reserved partition from another machine, then restored it on a HDD located in the disk slot #1.
The Mac still does not see the SSD when I turn it on while holding down the Alt key, however I can boot to it by selecting the HDD identified as a Windows disk. The boot code found on the reserved system partition is usually only useful when booting from encrypted disk drives, but in my case, it allows me to boot from the SSD card, as its BIOS is set up after the Mac handles the boot media selection.