I've moved this to the scripting forum. If anyone knows, it will be the users here.
This will do it.
But see also http://forums.adobe.com/thread/1082984?tstart=0 for a better workflow.
For some reason the OP over there didn't get back to say thanks and mark the answer as correct .
Thank you so much! However I am very new in indesign and I even don't know how to add this script into my document
I hope I am not being a pain! Could you help me on that?
In InDesign go to the scripts panel
Alt +(Ctr / Command) + F11
or Ctrl enter then type scripts and select script panel
or go to Windows / Utilities / Scripts
Then on the panel right click the user folder and click on the USER folder and click on reveal in explorer
You now have have the script folder open
Copy the above script and paste it into any text editor.
Save it in the script folder with the extension .jsx
Alphabetical Page Sort.jsx might be a good name to choose.
Lock in the script panel and you should see the script there in the User folder
Click on it to run it.
If the script does not appear there then close and reopen the scripts panel.
I think Peter would agrea that the correct answer should go to me and not him
Absolutely, and I've made the change.
You're lucky I'm still subscribed.
Thank you... very much appreciated and helpful!