We (always) have a limited number of Doc Sources supporting the Doc Addendum, Replacement, Transformation & Folder Mgmt option.  We have updated the test today (Wed am) to show that a Registry can use the NIST toolkit to test these features if you cannot find an available Doc Source.  We still prefer that you test with a vendor (and it's a better test), but we will allow you to complete the test with the NIST toolkit as an alternative.