How to add new applications to System lockdown approved list

SEP 12.1Ru1Mp1 - After creating the fingerprint list , running the system lockdown in testmode - gathering all applications and then enabling lockdown,

How do I add a new application that was never part of the fingerprint list .

Do I move the machine that has the new app to a test group >> set it log >> wait for the unapproved app to show up (which log can I find this ? >> add the list to approved list of applications or am I supposed to re0run the checksum.exe and then merge it with the older fingerprint list.

If I have to merge it - can I do it on the fly or should I move the policy to test mode and then update the list and then move it back to system lockdown?