Custom workflow - output parameters

Hi,

I have developed custom workflow and I need to "show" output parameters.

 [Output("ErrorText")]
 public OutArgument<string> errorText { get; set; }

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 errorText.Set(context.CodeActivityContext, "Error message : " +  some error text);
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I don't know where this text will be show, I suppose in

But I don't see my message....

If I am wrong please help me...

Thanks in advance..

Kind regards

Martin