Sorry, there is no solution for making the caption appear when clicking a button.
You can achieve something similar using floating-caption positioned top right and set hideOnMouseOut to true. This will make the caption appear to the right of the image when the mouse is over the expanded image.
Example page: http://www.roadrash.no/hs-support/galle ... image.html
Hilde
Highslide Support Team
Overview of my Highslide sample pages: RoadRash.no
I think, it would be a great feature for highslide to do rightpanel caption appearing after clicking a button. It would fit perfectly on my commercial site. Is there any possibilities that you could do that?