Force Developer Studio 5.0 to compile *.C files in the same way as *.cpp

Is it possible to set Developer Studio to compile *.C-files in the same way as *.cpp-files?

I have a lot of C++ code made on UNIX using *.C. The code isn't UNIX dependent and I would like to use the code on Visual C++ as well. But Developer Studio only accepts *.cpp-files.

Can somebody help me?

Add /TP to the compiler command line. This makes the compiler treat all files as C++ source code.