How add a digital signature to RTF Template Using XML Publisher

Hello Experts,

Using R12

Have applied Patch 14313664: DIGITAL SIGNATURE SOLUTION NOT SUITABLE FOR USE

and understnad that "One digital signature per install, it is not dynamic."

QUESTION

Have a report, for example AR Invoice.
Want to send the Invoice with the Bursting Engine and at the same time
want to use a Digital Signature (not a digitalized signature), Like VERISIGN or ADOBE,
is there a way to embed the Encryption CALL on the Bursting engine at run time,
so the PDF generated will be signed digitally (Private Key/Public Key Logic)?

If yes, is there any example on how to embed the call on the Bursting FIle or on the RDF/RTF template?