Ok. Now I understand, but really can't be of any help with Outlook. I don't have Outlook and can't test what might happen. I do have a plan that should work.
If all your contacts are current on the iPad or other iDevice you can do this. Stop syncing on that device, and choose to Keep the contact database when you do so. Now you will have a backup that can be used to recreate the MobileMe address book if something goes wrong.
After that, go ahead and try to sync between Outlook and MobileMe. Keep in mind where your good address database is, and follow whatever prompts that appear accordingly.
If every thing goes well (after you've checked both on the computer and me.com that the address's are properly synced) you can turn the syncing back on, on the iPad. Choose to delete or the database when you are prompted. Delete will only delete the contacts on the iPad, and replace it with what is on MobileMe.
If thing go badly, choose to Merge the connects when re-syncing the iPad. This will copy the iPad's contacts back to me.com and attempt to merge hem with anything that is already there. That might result in duplicates, but you won't lose anything.
One other thing you can do to be on the safe side. Go to the me.com site, sign on, and go to Contacts. Once there use the gear icon to Select all addresses, then export them as a vCard file. Save this somewhere on the computer. You can use this file to reimport all you addresses if something goes wrong. You will probably lose all your groups this way, but it's a lot better than starting from scratch.