In the Printer Properties dialog for both the Adobe and Primo PDF printers,
there is a box to check that controls whether or not the Filename to save as
dialog is presented to the user and whether the result is displayed.  If the
filename dialog is not presented, the .pdf will be saved with the default
name which is the existing filename with .pdf substituted for the existing
extension.

The only way I found to specify the Acrobat file name is setting a registry
key. The key varies depending on the Acrobat version.  In all cases the key
is in the CurrentUser part of the registry.

Here is the code I use for versions 5, 6 and 7. Note that for this to work
the user MUST have set the printer defaults to
    a) not prompt for filename (no support for setting this via registry in
Acrobat 6)
    b) desired location for output files, or leave blank for source folder.
You can specify the folder (if I remember correctly) in the registry key
setting.

   'Setup for acrobat printing
   Select Case lngAcrobatVersion
   Case 5
       'Set the printer
       mobjWord.ActivePrinter = "Acrobat PDFWriter"

       'Set the registry value telling Acrobat the file name
       fSuccess = pjsRegistryHKCUWrite( _
        strSubkey:="Software\Adobe\Acrobat PDFWriter", _
        strValueName:="PDFFileName", _
        strValueValue:=strAcrobatFileNameWithPath _
       )
   Case 6
       'Set the printer
       mobjWord.ActivePrinter = "Adobe PDF"

       'Set the registry value telling Acrobat the file name
       fSuccess = pjsRegistryHKCUWrite( _
        strSubkey:="Software\Adobe\Acrobat\PDFMaker\6.0\Global\Settings", _
        strValueName:="PDFFileName", _
        strValueValue:=strAcrobatFileNameWithPath _
       )
   Case 7
       'Set the printer
       mobjWord.ActivePrinter = "Adobe PDF"

       'Set the registry value telling Acrobat the file name, _
        as per the Distiller API Reference. _
        This key will automatically be deleted once the next pdf file is
created _
        by printing to Adobe PDF printer from the specified application. _
        NOTE: This only works if Adobe PDF printer preferences specify
prompting _
        for the file name!
       'The registry key name must be the full application path and name.
       strWordEXEFullPathName = mobjWord.Path & "\" & "WINWORD.EXE"
       fSuccess = pjsRegistryHKCUWrite( _
        strSubkey:="Software\Adobe\Acrobat Distiller\PrinterJobControl", _
        strValueName:=strWordEXEFullPathName, _
        strValueValue:=strAcrobatFileNameWithPath _
       )
Paul Shapiro