VS 2012 Issue With WaitForExit On Process Started Externally

This is similar to another recent post of mine but a different problem.

Part of my app starts an external process (setup.exe) and I want to monitor that for when the process has closed but the problem is that the process is not called setup.exe its called launch.setup.exe

So I can't find a way (without using a loop which seems to just cause the app to stop responding) to monitor this.

Any advice greatfully received

Thanks