• Contact ID: user@gmail.com
• Password: password_from_your_gmail_account
• Disable the option "Scramble password".
• IP Address: talk.google.com
• Port: 5223
• Enable the SSL option, but disable the SASL option.

There is a second way:

• Contact ID: user@gmail.com
• Password: password_from_your_gmail_account
• Switch on: "Use secure connection" in the Connection tab
• Select: Use TLS and SASL authentication