Seagate/LaCie NasOS - enable volume encryption on non-supported device?

According to the guide at https://www.seagate.com/gb/en/support/kb/nas-os-4x-setting-up-volume-encryption-006007en/ there should be an option to encrypt a volume on devices running NAS OS 4.0. That option is missing from my LaCie 5big Pro although it is running NAS OS 4.0. According to the Seagate/LaCie support, the option is missing because my device doesn't support this feature. This is usually "a qualified truth", especially in the context of a Linux based OS. I assume the web based guide to prepare volumes is just an interface to a bunch of command line commands. I therefore asked the support for how to format and encrypt a volume from the command line but they refused to give me that information. The leads to a couple of questions 1. There should be a way to "eavesdrop" the command this guide executes in the background, shouldn't it? Maybe by following the process that way I could figure out how to prepare an encrypted volume. How can I "eavesdrop" this? 2. Anyone that knows how to do this from the command line? Or can perform (1) and figure it out? 3. Since NAS OS is Linux based it should be OSS and the source available somewhere (although not super easy to find, at least not for me) - any suggestions for how to figure out the answer to this question by reading the source (and find the source)? --- Edit: found the source code https://www.lacie.com/files/lacie-content/download/drivers/5bigNASPro_GPL_4.3.19.7.zip