Normally the FromAddress is used as the envelope-from address, but it can be overridden here, if it is not null.
[Visual Basic] Public Property EnvelopeFromAddress As EmailAddress [C#] public EmailAddress EnvelopeFromAddress { get; set; } [C++] public: __property EmailAddress* get_EnvelopeFromAddress(); public: __property void set_EnvelopeFromAddress(EmailAddress* ); [JScript] public function get EnvelopeFromAddress() : EmailAddress public function set EnvelopeFromAddress(EmailAddress);