¿How to work with virtual methods when creating a COM class?

Question

I am trying to create a COM class in .Net to interact with VB6. The idea is to integrate Crystal Reports into the .Net library, and this can be used in VB6. As I understand it, some methods work in the VB6 environment, but when I try to execute a method that uses a virtual function, the application stops working (freezes).

This is a virtual method:    public virtual void SetDataSource(DataSet dataSet); which has 4 overloads.

This is the method I execute from VB6:

public void fillReportWithDataSet(ReportDocument pReport, DataSet pDataSet)
{
    pReport.SetDataSource(pDataSet); // Virtual Function
}

When I execute other methods that have overloads, it still works, but these overloaded methods are not virtual. ¿Why does it stop working? ¿What is the correct way to use this method?

thanks