Write Japanese text into an existing PDF

PHP List, I am looking for a way I can create a PDF file by overlaying text onto an existing PDF document. I have found three open source script sets that seem to do that, but I can't figure out exactly how they inter-relate. They are TCPDF, FPDI, and FPDF. >From what I can tell, FPDI (which runs on top of FPDF) can overlay text onto another PDF, but I can't get any examples to work, so I am unsure of its stability. Also, I need to output Japanese text, and the documentation indicates it only supports Latin based fonts. TCPDF seems more fully featured and promises multilingual support. But for the life of me I can't find any single example of whether or not it can take an existing PDF and write text over top. Surely this is possible and has been done to death before. Can anyone direct me to a tutorial or sample script that I can use in order to set up this PDF generation script? Thank you for any advice. -- Dave M G