Call FinalizeStream as a final step when assembling a multipart form to represent a SOAP packet and its associated attachments. When an application assembles a multipart form to represent a SOAP packet and its associated attachments, it takes the following steps: 

1. Call CreateMimeStream to create the stream object that includes data from the SOAP envelope and the content of any attachments. 

2. Call AddSoapHeader to add any headers to the SOAP envelope portion of the stream. 

3. Call FinalizeStream to indicate that all changes are complete and allow the MIME attachment handler to make any final changes. 

Only after a call to FinalizeStream can the application read the assembled multipart form by calling GetMIMEStream. 

CreateMimeStream 

AddSoapHeader 

GetMIMEStream