I have created a sample project for you, demonstrating how to pass the TaskID on double-click event at server side. This could be achieved, by manually triggering an AjaxRequest, which could be handled on the server. Please find the attached website, demonstrating this implementation.
You've posted the same question in the following thread:
http://www.telerik.com/forums/client-event-double-click-task
Please continue the discussion only in that thread, to prevent unwanted clutter. I would also ask you to only post your questions in one thread (or open a new one). We monitor all active threads, and multiple posts may only cause confusion and clutter.