How to send an email in RTF format using EWS?

I want to send an e-mail in Rich Text Format (RTF) using the EWS (Exchange Web Service) API

  ExtendedPropertyDefinition RtfCompressed = new ExtendedPropertyDefinition(0x1009, MapiPropertyType.Binary); 

                    PropertySet propSet = new PropertySet(BasePropertySet.IdOnly, EmailMessageSchema.Subject, RtfCompressed);

                    EmailMessage email = EmailMessage.Bind(wsExchange, emailID,propSet);

I would like to know if these parameters are the same as step for the ExtendedPropertyDefinition and PropertySet