Two questions:

Can a work item be customized with a button(s) that launch my own application (such as a C# app)?

And, through the interface that TFS provides, can my application add a table(s) to the TFS database - which stores my application's specific data associated with a work item?

For example, I'd like to create a WinForms application that reads / writes additional data to be associated with a work item. The work item itself, when presented in TFS, would not necessarily show or know about this additional data (hypothetically, the data is kept in a seperate table managed by my application which relates to the work item via a SQL join).

If the answer is "no," then does TFS at least programatically expose unique ID's of work items - so that I can the ID's as a foreign key in a seperate database?