You might want to also check with Datalogics to see if they still have the Reader Extensions available with their Java Toolkit: http://www.datalogics.com/company/press/adobe-pdf-java-toolkit-and-adobe-pdf-java-toolkit- with-reader-extensions-now-ava…
Thanks very much for the response. I've contacted the datalogics folks and they've been very helpful (got a test version of pdfjt). I haven't actually built out a test for this (gonna do this today) but it seems like this would be more involved. Do you know if the datalogics extension key/certificate can be embedded in existing forms - without having to build the forms through the pdfjt? If this is how these sorts of tasks are accomplished - then I'll move in this direction but it does seem like one should be able to embed the key (even manually if needs be) without all the overhead of a server-based solution.
You don't need a server to run LiveCycle enabling solutions, but you do need a separate app or developer tool which signs and changes the entire PDF. It isn't just a key.
It's actually easier to enable the forms using the pdfjt than with the LiveCycle Reader Extensions, which does require that you set up a server, though I believe it can be on a workstation. The Datalogics people will be able to provide more guidance.