iPad messaging

The pad simply needs a unique e mail addrss. A phone number will not work.

If you have one, enter it in settings, messages in the receive at field. Apple will verify the address my sending you an e mail to that address. You need to respond to the e mail to show them you are who you say you are.

Then when someone wants to iMessage you, they should do it to the address you have entered.

If you have an apple I'd, you already have a valid e mail address on file. You can use that. If you have more than 1 apple device, and want to have messages to the pad only, then you need to enter the unique address as described above.

If you do not have a second e mail address, hop over to gmail and create a free account with a new address. Remember, apple will verify the address by send you an e mail that you need to respond to.

I just re read your question. I message does not have anything to do with syncing. What is it your are trying to do?