I managed to find a not too elegant solution, but it works. In the plugin’s css file set the .nivo-caption class’s height to 100% and uncomment the background part.
Now you have a huge div for your captions. You can now add an other div in the Meta slider admin interface to the caprion field like this:
<div class=’slide_1′> Some text or random HTML code </div>
As a last step customize the slide_1, slide_2 etc divs from your css. Add some background with opacity (also you need to add a height to the div or you won’t see it), and position it where-ever you want. (position: absolute; left: x px; top: y px;)
Hello! Did you manage to solve the problem? I would need the same feature.