I need to create a package for an application. This application is an addin for an other application which is already installed. I have to use a COM-dll to get an install path for my application.
Here is the setup sequence:
- unpack and register a dll;
- get a destination path from the dll;
- unregister and kill the dll file;
- install my application in a specified path.
How can I do this using MSI? There is no any custom action before unpack

I use MS Visual Studio.NET to create the setup.
Thanks.