Replies to email notifications - experiencing problems

I haven't heard back from support yet and wanted to hear what other users might know about this problem.

The problems I am having now are:

The Sender name (in the mail settings - Outgoing Tab) is not being sent. I have "companyxyz service desk" in that field, and a "noreply@companyxyz.com" in the reply to address to deter responses.

I notice the application will append replies as updates to the ticket, and although this is a wonderful featuer, I find it doesn't work all the time... sometimes it works, and sometimes not.

What are the necessary conditions for the software to do the APPEND feature, because I can't figure out why sometimes it works and sometimes it doesn't.

thanks,

Alex