I realize this isn't a very good answer, but:
1. I think it can't be done. But it doesn't seem to be using a heap of processor time, so no big deal.
2. You can, at least, make it stop doing whatever it's trying to do. (In Settings > Accounts > Backup Assistant Plus, you may find that yours is set to back something up. I discovered that mine was set to backup my contacts, when I don't recall ever asking it to do.)
3. You can get rid of it from the VZW end. Which is to say, you can log on to your account at Verizonwireless.com and eliminate Backup Assistant Plus as a feature on your account, although the app will remain on your phone. (I was forced to do this in the middle of Heathrow airport because, upon my previous phone's arrival in another country, it decided to send me very annoying alphanumeric text messages, which were somehow related to Backup Assistant and the stock email program. I never did figure out exactly what was going on, but getting backup assistant off my account stopped the problem. The whole process ended up killing my stock email, though, so use with caution. I switched to K-9 mail and never looked back.)
Sigh. It's crap like this which makes me think I should have waited and ponied up the cash for the Google Edition of this phone. But I grit my teeth and accept that I'm just stuck with VZW bloat for the next two years.