I have been looking for a solution, and have now finally pieced this together.
I hope it helps others:
Using Outlook 2007 on a dual boot system with Vista Home Premium and Windows 7
Assumes that Vista already has a working copy of Outlook installed
1) install Windows on Windows 7
2) boot to Vista and UNHIDE the following directory:
users/<username>/AppsData/ (apply change to subdirectories and files)
To export Account details (to avoid setting these al up by hand)
1. Start > Run > type ‘regedit’
2. Locate the following path in your ‘Registry Editor’
3. HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows Messaging Subsystem\Profiles\Outlook
Now right click on the key outlook and select option: Export and save .reg files to the root of your C drive.
The boot windows 7
with file explorer find the saved reg file. (The c drive will be shown with a different drive letter) double click to import.
Then open outlook. It will report that your pst (or several incl archive) cannot be found.
This is because the paths it is looking at have the C; infront. click ignore, go to Tools/account settings (you will see you email accounts here Magic!) click on the data files tab, click on settings and change the path to the path on the Vista drive. (possibly d: drive. rest of path will be the same.) You must have permissions to access and have remembered to unhide the Appdata folder as mentioned before.
Do this for all the pst. files.
Close outlook and restart.
You will need to enter your passwords for the email accounts as passwords are not stored into .reg file! (save password ticked if you do not want to repeat this.
Finally, if you use colour categories, check your calendar to see if the have reappeared. If not, right click on the Today screen top bar (click on personal folders and the Today screen will appear) and press Properties and the "upgrade to colour"
voila! done. (I then install my preferred free add in XOBNI. highly recommended)