that would be only possible by creating additional elements - e.g. either additional overlapping hotspots - or - <layer> elements with parent="hotspot[NAME]".
In both cases the textfield plugin need to be used to display the text.
Is there a way to have an exemple of code ? On the tablet it's very interesting to know where you are going to click, if we could show the title of the linkedscene just under the png for exemple.... I made some tests but i can't succeed. Someone knows how to ?