rEFInd and _two_ FREEBSD systems on the same disk on the same UEFI laptop

[salvatorembartolotta at libero.it]

Good afternoon,

Has anyone installed two BSD (say -RELEASE and -STABLE) on the same disk on the same UEFI machine using rEFInd?

Setting up dual booting - Windows 10 and FreeBSD-whatever - via rEFInd is just a matter of bcdediting a path and copying the appropriate .efi files. (duh).

The /boot/boot1.efi copied in \EFI\FreeBSD-STABLE does its job and loads the _first_ FreeBSD system, as says uefi(8).  What if I want to boot _another_ FreeBSD system on the _same_ GPT-partitioned disk?

Specifying the GUID of the partition in the menuentry stanza i.e. 
...
volume GPTGUID 
loader boot/boot1.efi
....

isn't enough and does not work(TM).

I suppose rEFInd_x64.efi can't access the second system without an appropriate ufs driver.  There are, indeed, drivers for linux filesystems (ext2, ext4, etc.) in the rEFInd directory.  And FreeBSD?

How am I supposed to solve the problem _within_ FreeBSD with rEFInd?
 
My apologies for the crazy/mad question and many thanks in advance for your help, pointers, suggestions.