How do I check a list of c++/cli ref items for contains?

A c++/cli ref class DataEntity implements Equals and HashCode. I can check the behavior of the Equals implementation via:

entity1.Equals(entity2);

(C# source) and it works correctly. If I now have a list of such DataEntities and I call Contains(entity) on that list, the Equals method never gets called.

What is the reason for, and how can I use the List.Contains(...) method correcty?

According to the MSDN documentation, the method Contains(...) calls Equals(...)

Example:

C++/CLI source:

public ref class DataEntity : System::Object
{
public:
    DataEntity(System::String^ name, 
        System::String^ val) 
        : m_csName(name),
        m_csValue(val) {}

    System::String^ GetName() { return m_csName; }
    System::String^ GetValue() { return m_csValue; }
    virtual bool Equals(Object^ obj) new {
        if(!obj){
            return false;
        }
        DataEntity^ other = (DataEntity^)obj;
        if(other){
            if(m_csName->Equals(other->m_csName) &&
                m_csValue->Equals(other->m_csValue)){
                    return true;
            }
            return false;
        }
        return false;
    }
    virtual int GetHashCode() new {
        const int iPrime = 17;
        long iResult = 1;
        iResult = iPrime * iResult + m_csName->GetHashCode();
        iResult = iPrime * iResult + m_csValue->GetHashCode();
        return iPrime;
    }

private:
    System::String^ m_csName;       
    System::String^ m_csValue;
};

C# source:

DataEntity entity1 = new DataEntity("Name", "Value");
DataEntity entity2 = new DataEntity("Name", "Value");
Console.WriteLine("Entities 1&2 are Equal: " + entity1.Equals(entity2));

List<DataEntity> entities = new List<DataEntity>();
entities.Add(entity2);
Console.WriteLine("ListContains_Entity2: " + entities.Contains(entity2));

Output:

Entities 1&2 are Equal: True
ListContains_Entity2: False