Invert a page on two of the PDF

Hello!!

Sorry for my bad English. I am going to try not to make too much error .

My problem is easy, but answer not.

I would like to automatise operation to invert a page on two of the PDF. I explains.

I've lot of PDF of 2, 4, 6 ,8 ... pages.

For example for a PDF contains 2 pages: 1,2 > 2,1

For example for a PDF contains 8 pages: 1,2,3,4,5,6,7,8 > 2,1,4,3,6,5,8,7

I've no idea with adobe pro, but with Ghostscript et Psutils it's possible, i've tried to create:

pdf2ps c:\chemin\fichier_original.pdf c:\chemin\fichier_moins_original.ps

pstops -pa4 2:0,1U(21cm,29.7cm) c:\chemin\fichier_moins_original.ps c:\chemin\fichier_plus_tourner.ps

ps2pdf c:\chemin\fichier_plus_tourner.ps c:\chemin\fichier_original_tourner.pdf

I thinks it's possible to create same code with postscript on adobe but i don't know how to do.

If anyone would like to help me..

Thanks for your answer.

Best regards all.