File source in parent directory

Topics: Ecosystem, General
Dec 14, 2013 at 4:23 PM
My C# project is setup as follows:
./bin/Debug
./bin/Release
./src/Project1/Project1.csproj
./src/Project1/Project1.csproj.nuspec
./src/Project2/Project2.csproj
./src/Project2/Project2.csproj.nuspec
...
The binaries of all projects are placed under ./bin/Debug or ./bin/Release.

I am trying to reference the binaries from the Project1.csproj.nuspec files as follows:
<files>
    <file src="../../bin/Release/Project1.dll" target="lib/net20" />
</files>
but I am getting the following error:

Attempting to build package from 'Project1.csproj.nuspec'.
Invalid assembly reference 'Project1.dll'. Ensure that a file named 'Project1.dll' exists in the lib directory.

How can I solve this?

This is an established project with 8 years of history, so it is not possible to change the directory structure.