If you're asking about Java Web Start, this is not supported directly by Tersus, and we have no experience working with it. You could try to create a hyperlink using HTML Tag, with the relevant URL (starting with jnlp:). It may or may not work depending on the client installation and browser.
If the question refers to starting a client session in the browser (connecting to an already running application), then you can use Go To URL (see http://www.tersus.com/?Id=5517).
For best results, use the Firefox browser..