using PDI to pull from data already read into a variable?

I have written scripts to upload pdf files into mysql. I have the scripts created to access those files and produce them for the user on the fly. All well and good. Now I have a need to access one of those files and insert its contents into a new pdf report. I have purchased the PDFlib+PDI and want to pull the data from the variable returned from mysql. However, the function for openning the pdf document to be inserted is looking for a file on disk to access. Has anyone done this without writing the document to disk first and then openning it from there? It seems that pulling it from the db in a query and then "handing" it to the PDI functions would be less intensive than writing it out, parsing it, and then ultimately deleting it from disk again. Any help would be greatly appreciated... TIA Larry