How Michael Biehn could be brought back in the Terminator series?

Like many i'm a huge fan of the Terminator series and a fan of Michael Biehn and well movies all together anyways today I was just reading how Arnie is interested in starring in T5 if he see's a good script. I was thinking how could they bring Michael Biehn (Kyle Reese) back to the Terminator series with todays effects to make him look younger Eg: Jeff Bridges went back 20 years for Tron Legacy. Just a thought :P What do you think? And how do you think they could write a script to bring back Arnie and Biehn while staying true to the story? Any input is appreciated! Thanks!