Item.Save throws exception on derived class

[nathandace]

I have class that is derived from EmailMessage, so that I can inject some logic into the EmailMessage.SendAndSaveCopy().

However, Save() and SendAndSaveCopy() fail when called from the derived class due to an XML serialization error:

The empty string '' is not a valid local name.

Looking into the source code, this is because ServiceObjectDefinitionAttribute is missing from the derived class. Because this attribute is internal, I cannot add the attribute to my derived class to get past the XML serialization error.

My derived class is fairly straightforward, which demonstrates the exception that is thrown when calling base.SendAndSaveCopy()

public class CustomerEmailMessage : EmailMessage
{
     public CustomerEmailMessage(ExchangeService service) : base(service){}

     public new void SendAndSaveCopy(){
     {
          if (isEnabled)
          {
               base.SendAndSaveCopy();
          }
     }
}