This solution uses the Application "Automator" which is already on your Mac.
1) Order your photos by naming them 001_FileName.jpg, 002_FileName.jpg, etc.
(use 001.jpg not 1.jpg as it won't work past 9.jpg)
2) Download the Automator Action "Touch File" and Install it (Follow insructions, really easy)
http://www.macupdate.com/app/mac/32413/touch-files
3) Launch Automator
4) Choose "open an existing workflow"
5) navigate to and select "Touch Files.workflow"
6) In the Finder, select the folder containing your images
7) In Automator, change the Creation Date and the Modified Date to whatever you want
8) Check the box "Apply to contents of folders"
(This will change the creation date and modified date for the folder you have selected and everything in it)
9) Sync your iPad photos with your folder in iTunes
This works for me every time.
Hey Apple, how about giving us a sort option in iTunes Preferences?