Hi,
I tested the option "Use Joomlas mail name and email" in Joomla 2.5.10 and Joomla 3.1.1.
In Joomla 2.5.10:
The e-mails are sent from the sites e-mail (correct), but when I reply it doesn't use the sender's e-mail address, but the site's e-mail.
In Joomla 3.1.1:
The "From" address is a mix of the site e-mail and the sender's e-mail (see attachment)when replying:
"Site name" <site_email.domain> sender_email.domain
Also when using the return key on the keyboard to make line breaks in the message they are shown as \r\n:
"hej,\r\n\r\ntest"