How to Backup Up KMS files

Hi, our customer's appliance is NBU5230 appliance (2.6.0.3), which is the only NBU server in their environment. Recently they plan to implement KMS in the appliance. I did some checking and found for normal master server, we can back up the KMS files (KMS_DATA.dat, KMS_HMKF.dat and KMS_KPKF.dat) for DR purpose. 

My question is:

For the appliance, how to back up these files? Thanks in advance.