Mail to CASE questions, 7.9.2

Good day to all Community
Recently installed on Ubuntu server SuiteCRM 7.9.2
Main task is help for our support team, so main feature to use is “email to case”
So what I did is:

  1. Created Security group with few Support users included.
  2. Set up SMTP settings for outgoing mail
  3. Set up setting for incoming mail with “allow users send emails using the “from” …”
    Create Case from Email: yes
  4. Disabled all Auto-answers in AOP settings
    5.In Email settings enabled such positions:
    Assigment Notifications:YES
    Send notification from assigning users e-mail address: YES

So here some questions/troubles I have:

  1. When support users receive mail it creates CASE, but when support reply on this letter NOT via SuiteCRM but his mail Account with (this is our support mail, for example) in copy we recive another mail with subject “RE:…” and SuiteCRM creates next case with name RE:
    Is it possible to make answers RE:/FW: be availible in one CASE?
    P.S. in History part of CASE I can see, that Mail with CASE subject is Unread. (maybe this could clarify my situation)
  2. When I reply in CASE via CASE UPDATES - I dont receive email with update (or I shoudn’t?)
  3. When we receive mail on our mail it automatically assigns responssible person for it. This person Recives 2 mail:
    First one is that case is assigned for him
    Second one is totally empty, with no subject or text in body of email.

If there anyone who can give ukrainian/russian manual it would be also great.