There's always the option to create specific labels, just using Text Tool, and perhaps an ellipse or rectangle - something like that. But it sounds like you need something approaching automatic, to create them.
Again, an extension....or it wouldn't have to be an extension. The only reason for making an extension would be so that other users can benefit. But just for personal use, a script might work. Or else Inkscape has commandline ability. It seems like I've heard of using the commandline for something like this.
Although I'm a little lost with "implantation", "exposition", and "exposant". So I might be going down the wrong road. (well, I could give a definition for all 3 words, but not sure about a situation of using them all together) ("science" is as close as I can get, haha)