Printing text to Acrobat PDFWriter in VB

I use VB Printer.Print() to print couple lines of text to a printer.
It works fine with regular printers. But when I select PDFWriter as the default printer and print, the .pdf output file doesn't contain the text I print out. For ex, Printer.Print "aaa" could generate a .pdf file contain "DDD".
I guess this is related to font settings but I don't know how to fix it.
Please help,
Many thanks