Installer drops administrator privileges too early, can't create maintenancetool.exe

This issue can be demonstrated using the tutorial example:

1. Create the installer binary for the tutorial in examples/tutorial.
2. Run the installer
3. When asked to choose the install location, select a location which requires administrator privileges to write to. I chose "C:\Program Files\InstallerTest" in my test
4. Accept the default values for everything else, click through to install.
5. When it starts the install, it will request administrator privileges. Click yes to allow it.
6. It will install the data, but will fail to install the maintenancetool. See attached screenshot and installation log for error message.

I suspect that it's dropping its elevated privileges too early. If the entire program is run as administrator from the start (by right clicking and selecting "Run as administrator"), then it can successfully write everything to a privileged location.