Well Biagio, the code I gave you previously is what I expected you to put where you just put the abbreviated code you just listed. My code added a couple of features you might want to incorporate. The first is to add the noshow/endnoshow/showpage to keep the datasheet from flashing at all. The second feature is to test to see if you are currently at the top record of the datasheet so you would have to go down a record and then back up. In all other cases you would go up a record and then back down. In you simple code nothing will happen if you are currently on the first or top record.
Obviously the choice is yours.