Inserts the text contained in MessageText into the Message field of the currently active compose view. The text is either appended to the message, or replaces the text of the message, based on the value of Append.
AFTKN_SET_MSGTEXT or 571
VOID TextSetMessage( ANSISTRING MessageText; [BOOLEAN Append])
Text to insert into the message.
(Optional) Specifies the following:
The message body field (in the Message View and the Object API) has a limit of 32,000 characters. The Message View will stop accepting data after 32,000 characters.