I have a license for PDFBlackbox, XMLBlackbox or PKIBlackbox. How do I use timestamping?
You can perform timestamping using one of the components: TElHTTPTSPClient and TElFileTSPClient.
The first component makes use of TElHTTPSClient, which is covered by HTTPBlackbox or SSLBlackbox packages license. TElFileTSPClient lets you send TSP request and pass the response to timestamping code yourself, using any transport you need (such as HTTPWebRequest for .NET or Indy HTTP client for VCL).
You don't need any extra license for TElFileTSPClient, but you will need to implement HTTP connectivity yourself. It is trivial (about 10-15 lines of code) once you read the corresponding section in RFC 3161.