If the talent won't or can't do it, I say take down their web page. Drop their blog. Banish their tweets. Kill their Facebook. If they will not jump in with both feet then don't pretend they did. Don't insult the intelligence of your audience, please. Users of these tools know the difference between a volunteer army of tweeting station representatives and a conscripted, stodgy crank who needs support from the IT guy every time his computer goes to sleep.
I once thought pushing non-social-media people to get into the game was the way to go. Otherwise, who would do it?
But I learned the hard way -- multiple times -- that if they don't want to, you can't force them. Because if they're forced, it'll look / feel / sound like they were forced. And no one wants to be around a cranky tweeter or facebooker or blogger.
Some people are not built to communicate, to share, to participate. They just aren't. Others can learn to do it, and can even learn to do it well. I know *I* have learned to do it (although I had a lot of writing experience from college days that helped).
But if someone just isn't interested, you can't make them do it, much less do it well. You either care or you don't.