Normally this requirement can be achieved. In fact this can be done in PI Server 2012 a lot faster and easier than any other versions. But depending on the type of historical system you are working with, we would have different recommendations for the best way to proceed with this. We refer to this process as backfilling, and an introduction to this process of backfilling data to PI System can be found here: www.youtube.com/watch?v=3wzBlqBH5cU
If you have more questions about this, I would recommend that you get in touch with our Techsupport Team for more assistance.