Delphi Access Violation calling a C++ DLL that implements an interface - c++

Question

To import a DLL in Delphi I've written a unit translating a .h file
This DLL allow me to define a procedure to monitor two values and use them in my app.
the original .h file is:
class MyINTERFACE
{
public:
virtual void MonitorProc(int value1, int value2) = 0;
};
extern MY_API MyHANDLE* Init();
extern MY_API UINT InitMonitorProc(MyHANDLE * handle, MyINTERFACE * pMyProc);
and this is my translation:
unit myCdllUnit;
interface
const
TMyHANDLE = DWORD;
MyINTERFACE = class
public
procedure MonitorProc(value1: longint; value2: longint); virtual; cdecl; abstract;
end;
function Init(): TMyHANDLE; cdecl; external 'myCdll.dll';
function InitMonitorProc(handle: TMyHANDLE; pMyProc: MyINTERFACE):DWORD; cdecl; external 'myCdll.dll';
implementation
end.
in my main form I override the MonitorProc (initially only with "inherited" to test the calling)
TMyMonitor = class(MyINTERFACE)
public
procedure MonitorProc(value1: longint; value2: longint); override;
end;
procedure TMyMonitor.MonitorProc(value1: longint; value2: longint);
begin
inherited;
end; <--------------------------- here get an Access Violation
and in my FormCreate I pass an istance to InitMonitorProc
MyMonitor := TMyMonitor.Create;
InitMonitorProc(Handle, MyMonitor);
the DLL is calling correctly but exiting MonitorProc I get an access violation error.
Where am I wrong?