To print custom file formats via virtual printer driver, the associated application needs to support the command verb “print”.
A quick way to test this is right clicking the file to show the context menu and see if “Print” is one of the options.
If the print verb is not present, then PDFNet cannot use the perform the conversion.
Assuming that your associated application supports command line printing, you can manually add the print verb through modifying the registry.
-look for value of “Progid”, this could be under HKEY_CURRENT_USER or HKEY_LOCAL_MACHINE
-Under this entry, you are looking for the “Shell” key. Add the “Print” key, with “command” and data as the command-line code to perform print.
For example, if you set your default program to open .docx with Wordpad….
Since Wordpad in Windows 7 can open & print Word (docx) files you may want to try associating these files with Wordpad.
Ø Progid REG_SZ Applications\Wordpad.EXE
Ø Add key “print”
Ø Under “print”, add key “command”
Ø set default value to the command line code for printing
Ø (Default) REG_EXPAND_SZ %SystemRoot%\system32\Wordpad.EXE /p %1
Resources on setting command verbs
After you made your changes to the registry, try to print from the context menu with the “print” command.
If that works successfully, PDFNet should also be able to convert the file.