Delphi/pascal: overloading a constructor with a different prototype

I'm trying to create a child class of TForm with

1. a special constructor for certain cases, and
2. a default constructor that will maintain compatibility with current code.

This is the code I have now:

interface
  TfrmEndoscopistSearch = class(TForm)
  public
    /// original constructor kept for compatibility
    constructor Create(AOwner : TComponent); overload; override;
    /// additional constructor allows for a caller-defined base data set
    constructor Create(AOwner : TComponent; ADataSet : TDataSet; ACaption : string = ''); overload;
  end;

It seems to work, but I always get the compiler warning:

[Warning] test.pas(44): Method 'Create' hides virtual method of base type 'TCustomForm'

• Adding "overload;" after the second constructor won't compile. "[Error] test.pas(44): Declaration of 'Create' differs from previous declaration".
• making the second constructor a class function compiles without any errors or warnings, but dies with an access violation at runtime (all member vars are nil).