Add two features to an existing ASP.NET website

The website is [login to view URL], developed with ASP.NET/C# and SQL2008. Add the following two features: 1. Each escrow transaction has a unique ID which is currently a GUID. Change this to a letters-only unique ID (there should be no numbers in the ID). This needs to be changed in the database (UNIQUEIDENTIFIER -> VARCHAR), throughout the code (Guid -> String), and also when the ID is first generated (need to implement an algorithm to generate a unique ID). The new ID algorithm should generate strings that are long enough so they are not easily found with a brute force attack, and also unique enough that they are not sequential (i.e. I cannot change a letter in an ID to get another valid ID). 2. Messages sent from the site are currently delivered by email. Add functionality to also store and display the messages on the escrow page, much like an online chat. A refresh button should be added to the page for checking for new messages.