How can I create a PDF that conforms to PDFX/1-a:2001 form Pages

Question

I have a 358 page B&W document created in PAGES - I need to submit this to the printers (Lightning Source) as a PDFX/1-a:2001. I have Adobe Acrobat Professional and Distiller. However, pdfs created by PAGES cannot be converted by Acrobat into PDFX/1-a:2001 (at least I haven't been able to figure out how to!). The solution proposed by Lightning Source is to:
print to a Postscript file first, then process the PostScript file using Adobe Acrobat Distiller Professional Version 6 or newer.
This allows you to produce a PDF that is of optimal compliance with our printing process (PDFX/1-a:2001 recommended)
The problem is that when PAGES creates the Postscript file it doesn't retain the correct sizing - it shifts it from 216x140mm to Letter size (the original document shifts to the lower-left corner surrounded by blank page). This size change continues when Distiller creates the PDFX/1-a:2001 so their solution doesn't work.
Anyone who has actually achieved this or with suggestions - all advice gratefully received!

Answer 1

Peter, thank you for your suggestions - I was a bit daunted by the colorsync filters, etc., however, after much searching I've put together an apparent solution. I'll find out if it works in a few days when Lightning Source get back to me:
Creating a Lightning Source pdf from a Pages document
Here is a walkthrough of the process I go through to create PDF in the format Lightning Source requires for B&W inner text - PDFX/1-a:2001. You need PAGES, ACROBAT DISTILLER and ACROBAT PROFESSIONAL.
In PRINT dialog go to the PDF button and select SAVE AS POSTSCRIPT.
Open this Postscript file in Distiller, it should save it as PDFX/1-a:2001.
If the page size is incorrect go to the following instructions.
Your pdf should be ready now to go to LS.
IF THE PAGE SIZE HAS BEEN MODIFIED
This was my major challenge as OS X’s export to Postscript seems to modify the file to A4 or Letter size. You need the following Applescript (thanks to Gregory Ledger for this essential tool):
http://macproductionartist.wordpress.com/2009/04/01/really-cropping-pages-in-acr obat/)
tell application "Adobe Acrobat Pro"
tell active doc
repeat with i from 1 to count of pages
tell page i
set cbox to crop box
set media box to cbox
end tell
end repeat
end tell
end tell
With your new pdf opened in Acrobat Professional use the DOCUMENT: CROP PAGES dialog box.
Set the margins of the Crop Box to the required dimensions.
Keep the pdf open in Acrobat Pro.
Now run the APPLESCRIPT above - this modifies the pdf so that the page size is modified to match the new crop size.
Save your pdf and this should now be ready for use at LS.
Gregory Ledger also recommends exporting the cropped pdf to Postscript and then running this through Distiller again to ensure any artefacts are removed.
Thanks again for your time and suggestions, Richard