HeloDesk email box with Exchange 2010

hello Guys,

We have a requirement.

We have common email address call "helpdesk@contoso.com . 10 help desk agents use this email box and are sending and replying emails. Sender address should be "helpdesk@contoso.com. We had open source email server and used IMAP Accounts.

Now we deployed Exchange 2010 Sp2. We need to Achieve same goal.

1) When we use IMAP we cannot see the SENT items folder.

2) When we use Shared Mailbox, we cannot save sent emails in SENT Items folder.

We have Outlook 2007 and we cannot use Outlook 2010 at all.

Regards