Microsoft Office Live Small Business Community

I plan to do a full redirect (website and email) of my domain name to Office Live Later on, if I wish, I'm assuming that I will be able to switch to a partial redirect (i.e. only website). All I'll need to do is to go to my registrar and change the name server back to my registrar's name...

I have my prefered domain hosted elsewhere. I would like to use the Office Live Small Business for my Email and a website, but Not for all of my websites. So I would like to be able to redirect my MX record and a host on my DNS say live.mydomain.net. Is there a way to do this, or is all or all web, or...