ASP.NET helpdesk/customer manager

Looking for a asp.net helpdesk/customer manager software - something like AdventNets SupportDesk 5 ( [login to view URL] ) - with some changes to better fit our business. SupportDesk is designed for internal helpdesks, we need to have something similar built for dealing with external clients and billing. Specific changes include: -Ability to add companies rather than departments -Ability to track assets, software licenses and hardware by company -Improved time tracking capabilities, specifically ability to enter time entries for customers without a ticket and better time tracking within tickets. -ability to create and close tickets via command line, with node detials, from Whatsup Gold -Abilility to send mail to all customers, groups of customers or individuals. App should be in asp.net with c# or vb.net and ms sql server. App need to be web based. Exchange will be used as the in/out mail server. Client portal and staff portal will reside on different servers. Please provide demo of any existing help desk systems that you have, if you have any. Additional items to be added to this project are: -sync of tasks with outlook -dispatch calendar that syncs with outlook for each tech -Ability to create service invoices