Uploading past pdf transcripts for electronic delivery

We'd like to use Populi to process our transcript requests for USPS and electronic delivery, but we've run into challenges with not being able to upload old non-populi transcripts for electronic delivery. I'd like to see the feature added to upload a .pdf of older transcripts, with populi applying the the additional pages (transcript key, authenticity statement with receiver information). We are looking to use Populi for all transcript delivery in the near future if possible.