getting an event handler from a active-x dll dispinterface

I have imported a active-x dll into delphi for communicating with a
device trough com-port.

I managed to create an object with a sendmessage procedure and used it
succesfully. I now want to create events to receive messages but since
I only know for about 10% what i'm doing I don't know where to start.
Also I signed a non-disclosure contract with the firm of the device so
I can't be too specific I guess.

The sendmessage is formulated in a class in the wrapper something
like this

========================================
iMachineprotocol = interface(lDispatch);
['{blabla}']
function SendMessage(var Data: OleVariant): SND_STATUS; safecall;
function OpenPort(const bstrPortName: WideString): INIT_STATUS;
dispid 4;
function GetMessage: OleVariant; dispid 7;

MachineProtocol = class
class function Create:iMachineProtocol;
========================================
I can create an object
o := machineprotocol.create;
And use this object to open the comport and send byte-array
transformed to olevariant messages.
The device responds happily

But I can't GET messages, I would need an event handler for that I
guess.

The events-object(?) is formulated in the wrapper something like this:

=======================================
SomelEvents = dispinterface
['{blablabla}']
procedure Youhaveamessage; dispid 1;
end;
========================================


How do I use this in delphi?
I use delphi 4


.