mtx commands to open mailslot on HP MSL tape library

I want to programmatically open tape library via command-line. My HP MSL4048 have 3-tape mailslot and 4 magazines, which I can open from web interface only. Reading manuals I understood that opening mailslot or unlocking magazines commands are not standard and every vendor may have its own way to do this. Does anyone know commands to eject HPE MSL4048 mailslot or unlock magazines? I also believe that Quantum i40 or Sun Storagetek SL48 or IBM TS3000 library series have similar hardware and may have similar commands for both actions.

I have tried:

mtx -f /dev/sg2 unlock (does nothing)
mtx -f /dev/sg4 eepos 1 transfer 32 32 (give an error)
mtx -f /dev/sg4 eepos 0 transfer 32 32 (give Source Element Address 1032 is Empty)

and any other numbers after eepos.

Solution 1:

I checked all SCSI commands supported by HPE MSL. Unfortunately, there are no command to release the magazines. Hence, most applications including mtx are not able to do this. The only possibility was RESTful APIs, but this was not found neither.