Microsoft has a nifty tool called Orca.exe that lets you directly edit options within msi installer files and msp patch files.

Orca.exe is a database table editor for creating and editing Windows Installer packages and merge modules. The tool provides a graphical interface for validation, highlighting the particular entries where validation errors or warnings occur.

This tool is only available in the Windows SDK Components for Windows Installer Developers. It is provided as an Orca.msi file. After installing the Windows SDK Components for Windows Installer Developers, double click Orca.msi to install the Orca.exe file.
http://msdn.microsoft.com/en-us/library/windows/desktop/aa370557(v=vs.85).aspx

Orca.msi was originally included in the Windows Installer 4.5 SDK, which is no longer available as a stand-alone download. Orca.exe version 5.0.7693.0 and other tools for working with msi files are part of the Microsoft Windows SDK for Windows 7 and .NET Framework 4 (or for previous versions, try the older Microsoft Windows SDK for Windows 7 and .NET Framework 3.5 SP1). The package that includes Orca.msi is available as an a la carte selection from the Microsoft Windows SDK web installer. Proceed through the web installer wizard and then select only the “Debugging Tools for Windows” under “Common Utilities” for the minimum install. Orca.Msi will be saved to “C:\Program Files\Microsoft SDKs\Windows\v7.1\Bin\”.

If you prefer a massive download just to get a 2 MB executable, the entire Microsoft Windows SDK is available as a 1.4 GB ISO from Microsoft Windows SDK for Windows 7 and .NET Framework 3.5 SP1 (ISO).

Should Windows 7 be old news to you, you can try the Windows Software Development Kit (SDK) for Windows 8. (I have no idea what’s in there.)