No can't keep them,just hand them in at the licensing centre and then get normal plates for your car.
Tell them that you want the plates kept in storage, cause you will be putting them on another car later.
When you hand the plates in the operator will write it down in a book that they have for plate storage and returns. Just remember the date when you hand them in so that when you go back to get the plates tell them the date so it's easy to find in the book as to where they put the plates and get them back.
I did this 6 months ago. It will just cost a change of plate fee from memory. It's about $15 each time.
If they loose the plates they should get them reprinted at no cost to you.