If I wanted to have my corporate e-mail (Exchange) pushed to my BB 8700c, in addition to my corporate e-mail admins setting this up on our end, do I need to upgrade to the more expensive (by around $15/month more) "unlimited corporate e-mail" versus what I have now--the "unlimited Blackberry e-mail" from Cingular? Or does will just my admins allowing access provide the "enterprise activation" I need?

For that matter, if I signed up for an Exchange hosting service, do I still need the same service upgrade on the Cingular side?

I ask b/c I'd like to use the Exchange push rather than the desktop redirector if it won't cost me anymore...thanks for any guidance you all could provide.