Other implementation of singleton

[C#er]

For a class that has an explicit constructor with 2 parameters, I'm thinking to rewrite my Singleton. This idea is because the "getInstance()" method of Singleton. If the implementation of this method is like this:

static Singleton<T>::_instance = NULL;

template <typename T>
template <typename U, typename X >
T* Singleton<T>::getInstance( U, X )
{
   if( _instance == NULL )
      _instance = new T( U, X );
   return _instance;
}

Every time I call getInstance, I need to pass parameters. For the first time it's ok, but for another calls it's not fine to do this.

class MyClass : public Singleton<MyClass>
{
public:
   explicit MyClass( int, char );
   ...
}

But if I have a Singleton that receives the parameters and verifies inside their constructor, I think it works.

template< typename T >
class Singleton
{
public:
template <typename X, typename U>
Singleton()
{
   if( _instance == NULL )
   {
      _instance = new T( X, U );
   }
   T* getInstance()
   {
      return _instance;
   }
}
private:
   static T* _instance;
};

Ok, the problem for me is, is a good way to solve the explicit parameters in constructor with this solution? Is there a better way to do?

Any help is very appreciated.

Thanks