Platform Invoke - getting the DLL copied to the EXE directory

[Steve Terepin]

I have a Solution that consists of two projects, one written in C/C++ that
builds a DLL, and another written in C# that builds an EXE. I'm using
P/Invoke to call the DLL, and it all works just fine. However I haven't yet
found a really nice way to make sure that the DLL gets automatically copied
to the same directory as the .EXE file so that it'll be available at
runtime.
Currently I'm using a Post-Build step in the DLL project to copy the DLL to
the 'DEBUG' directory of my main C# project, but that's clearly not a
satisfactory solution. I've tried mentioning the DLL project as being a
Dependency of the C# project, but doesn't do the trick. And mentioning the
DLL in the C# project's References doesn't work, because the DLL is not a
valid Assembly.

What's the best way of doing this ?

Thanks,

Steve.