boost::optional<enum> fails with /CLR

[nobody]

-----
#include <boost\optional.hpp>

#using <mscorlib.dll>
#include <tchar.h>

using namespace System;

enum Numbers { Zero, One, Two, Three };

// This is the entry point for this application
int _tmain(void)
{
	boost::optional<Numbers> num;

    return 0;
}
-----

optional.hpp(347): error C2300: 'System::Enum' : class 
does not have a destructor called '~T'

I'm using boost 1.31.0; this fails in both VC7.0 and 
VC7.1.

Removing "#using <mscorlib.dll>" and "using namespace 
System;" gets rid of the compiler error, but then you 
can't use things like System::String*

Thanks,
   Dan

sourceforge.net@jdanielsmith.org