Hey,
How do I use the Windows forms designer, and produce native code?

what do you mean by "native code"?

Not the managed code C++/CLI produces.

Oh, you don't mean "produce" -- the compiler does not produce any code, native or otherwise, except for the templates when you create a project. What you are asking is how to mix managed and unmanaged code. Here is an article on MSDN which should apply to all .NET compilers.

Here is another article that shows how to mix them in c++/clr program. How to use that in Windows Forms? I have not tried it but I assume the technique might be very similar, if not identical.
[edit]Note: I tried that technique and vc++ 2010 express didn't like it. The article was written in 2003 and probably very obsolete.[/edit]