how can I respond to a message in gmail using smtp, but do not go as a new message but respond within the message read through IMAP?
Check this. This was done for Outlook. You can do something similar for SMTP.
Ok, thanks for your answer I will try to see what happens
what happends, it was successful ?
Well, it did not work for me, I tried to do with the forward but it did not mean the expected results.