FileIOPermission for Partial Trust to read files in BaseDirectory

For practice, I'm writing a partial trust WPF C# application using VS 2010. The program involves some sound, so I've provided some .wav files in the program's base directory.

To avoid problems at runtime, in the app.config file I have used:

Q: How can I provide read access to files only in the 'base directory'? Since the base directory is not known until the program is deployed, this seems to pose a problem. It seems I need to provide absolute paths for files and directories, according to the FileIOPermission documentation.

Thanks for your help!

philb222