This is just aggravating. I called RIM yet again, and got conflicting answers to my questions. One rep told me that although BEs 5.0 is technically not supported on SBS 2008, it will install, and they have other customer running it. He went on to say that although the documentation states it is unsupported, they have in the past, and will continue to support it, although they do recommend against it. In order to take advantage of the promotion, BPS must be installed in the environment already, which isn't really an option for the SBS 2008 box. So I was told to setup a temporary BPS machine, upgrade it to BES 5.0 via the promotion, then do a knife-edge cutover to the SBS box. In theory, this sounded like a good solution. Then it occurred to me that the knife-edge cutover involves installing BES 5.0 on the SBS and migrating the users from BPS. If I have a way to install BES 5.0 on the SBS without all the hooplah of a temporary BPS box, why would I bother with any of that?
I called again for further clarification, only to be told that it violates the EULA to have BES on the same box as Exchange (I cannot find this in writing for the life of me), and that it flat out will not install on SBS 2008. I was told to install a VM on the SBS machine (which would in turn violate the M$ EULA) to run BES. Upon a third call, I was told BES on SBS 2008 was supported and will work fine.
As for the compatibility matrix, it shows BES 4.1.7 and below to be supported on SBS 2003, which the 2nd RIM rep claimed was not true. He tried to convince me that the matrix does not show what you can install BES on, just what it will play nice with if in the same AD environment. This makes no sense to me, but I can't find anything saying the matrix is what you can install it on and not just what it will play nice with in the same domain.