Hi Mike,
First make sure that you check one of the lightbox options in the dialog, so that the Lightbox library is included with the output.
Here's the Lightbox used within in5 output: http://www.jacklmoore.com/colorbox/
The main question is: how do you want to trigger the Lightbox? 1) By click on the MSO, or 2) by a separate button.
Let's start with clicking the MSO, because that will probably be simpler.
Since the MSO is already in the HTML, it will be considered an inline object.
The code might look something like this:
$(document).ready(function(){ /*make sure the doc is available first*/
$(".slideshow").click(function(){ /*add a click event to all slideshows*/
$.colorbox({inline:true, href:$(this)});
return false; /*optional: prevent other touch events from being triggered on the slideshow*/
}
}
);
I'm not sure if all of the interactivity of the slideshow will carry-through to the Lightbox, but you can give it a try.