The registry file named "MindManager5AddInWizard.reg" in the Mindjet Dev zone for MindManager X5 did not work for my installation of VS 2005 RC1. My VPC installation is:
Windows XP Pro SP2
Visual Studio Team Suite RC1
MindManager X5 Pro
I created a file named "MindManager5AddInWizard71b.reg" containing:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\AddinWizard7.1b\MindManager 5]
Once I loaded this file and restarted Visual Studio 2005 RC1, MindManager 5 was available for me to select.