how to use XmlDocument in C++?

[quekky]

#using <System.Xml.dll>
using namespace System::Xml;

namespace abc {
class abc
{
	virtual XmlDocument*	GetXmlDocument(CFile file);
}}

have error:
d:\Visual Studio Projects\abc\abc.h(85): error C3383: abc::abc::GetXmlDocument' : in an unmanaged class, a virtual member function cannot have a managed type in the signature


how do i create and use an XmlDocument. Regex and other .net functions in C++? specifically, i wanna use these functions in emule