Hello Terrence
Unfortunatly there is no way to do it from the Embedded GUI. However you can use the Rest API or alternatively if you have an Virtual SVP deployed you can configure it from there:
https://knowledge.hitachivantara.com/Documents/Storage/VSP_E_Series/93-07-0x/REST_API_Reference_Guide/16_Encrypting_data#Backing_up_encryption_keys
Regards