Windows: How do I copy a custom build of Python into a directory structure matching an MSI install?

[Paul Moore]

I've got a build of Python (3.3) on my Windows PC. Everything is
built, I believe (core, all modules, HTML help, etc). I want to
"install" it on my PC (because tools like virtualenv expect a standard
install layout, and the checkout basically isn't).

I tried using Tools/msi/msi.py to build an installer, but it's making
lots of assumptions and it's just becoming a pain (it's started asking
me for certificates, and I need cabarc.exe). So I'm giving up on that
approach, and just want to move the files into the right places.

I can probably just copy stuff around till it works. I might even be
able to decipher msi.py and work out how the installer lays things
out. But I'm lazy, and I'm hoping that someone already knows and can
tell me, or point me to some documentation that I've missed. In
return, I'm willing to share the script I write to do the copying :-)

Can anyone help?
Thanks,
Paul.