Help Desk system?

Hi all!

Sorry for cross-posting, I'm not sure which place is better for such question.

I'm looking for a help desk system solution for Drupal. I tried one with promising name Support Ticketing System http://drupal.org/project/support but I don't see there any basic functionality for general Help Desk.

Let me describe the problem.

There is a website for a trading company, they sell parts for cars. Many customers need help with selection. For this we are using HESK http://www.hesk.com/ , which is very simple but has a number of drawbacks. Now we are migrating our website to Drupal and looking for another/better/integrated solution which includes HESK-like (read: basic) functions + some new:

1) Anonymous or authenticated client can create tickets of types like: general support ticket, website question, parts inquiry etc.
2) Every type has its own fields, CCK is fine for this.
3) After creating a ticket, the client gets UNIQUE ID of it.
4) Using this ID he or she can open it up again and see all activity like manager's replies, and post reply too until and if the ticked is closed
5) Managers visit admin section of system, see all incoming tickets of their type and may take new ones into processing.
6) A ticket, taken on processing by a manager is not available for other managers for replying until the manager finish processing.
7) Difference between anonymous and authenticated users is that authenticated users has history stored in their page while anonymous has only IDs.
8) All activity is duplicated via E-Mail.

Can Drupal do this?
Thanks.