How do I embed a font in a PDF with missing fonts?

Q: We produce a series of PDF documents which contain some machine
readable text on them. Neither of these fonts are available on the
workstations of users to whom these PDFs are distributed. The tool
that we’re using to actually generate the PDFs in the first place does
not support embedding fonts. So, my desire is to simply use the
pdftron sdk (http://www.pdftron.com/pdfnet/) to open an existing PDF,
and then embed the fonts. Ideally, we would introspect the file to see
what fonts are in use, and then embed a subset of the fonts on that
list. (Some of the fonts we know will be available on all of the
workstations, and we wouldn’t want to embed those for file size
reasons).