Use Microsoft word and digital certificates to notarize documents (USA)
I feel like the JPEG seal is the problem. why is it being used? the digital signature should be more than sufficient. the seal does nothing but complicate the whole process.

But lets assume you MUST add the seal. One solution is to keep them segregated. instead of appending the seal to the document, have both parties digitally sign the document. then afterwards have the notary edit the seal with the documents name and author name and date. then he can digitally sign that as well. sending both of these documents together as separate entities.

EDIT: on a side note, most notaries for any documents that I have used have a sort of cover letter they draft up stating they have indeed seen and verified the documents. This perhaps is the best place to put that seal. Since it already has the document name date and notarized author. A natural fit for the segregation method I stated earlier.