Probably old news to some, but with regards to the Windows 7 RTM, someone has packed up a nice, neat Exchange System Manager for Windows 7 msi package which accomplishes the same thing the procedures in this thread. Here's my flow of events, but I have a feeling it's not necessary to do exactly the same thing now that this package is out:
1. Installed the RTM, joined it to our domain (new install).
2. Installed the RTM RSAT update (different update than the RC)
3. Opened ADUC, enabled advanced view, closed it.
4. Ran the ESMWindows7.msi, accepted all prompts.
5. Off to the races. ESM (for our Exchange 2003 server) installed fine, worked normally, and the Exchange tabs in ADUC properties windows were present and function normally (so far).
This is the only place I've found the new msi:
ESMWindows7.MSI - download now for free. File sharing. Software file sharing. Free file hosting. File upload. FileFactory.com
Good luck.