Hi Stuart,
Thanks for your post. First of all, there is a bug in DBXL 2.4 Administration Tool that prevents "signed" forms from being correctly attached and saved. We are preparing a fix and hope to have it on the web site shortly. We will update this thread in the next week and also provide documentation. Sorry for the inconvenience.
P.S. We'd be happy to provide a private build to you via email if you need it sooner. Please send email and request if you can't wait.