Is it possible to add to and edit what attributes show up to summarize a work item in the Links section (eg Depends On) and the context sensitive hover boxes shown in the Quick Information?

It seems that ID and Summary attributes are used, but having customized a work item type with attributes that identify/summarize the work item I'd like to see those. I can't even use the Summary field in my custom work item, because my Abstract attribute needs to be restricted to a number of characters and if I add my Validator to the Summary attribute, it will affect the whole project and all the built in work items.

Any suggestions gratefully received
Rachel