You could create separate Inline Styles for figures (Abbildung), formulas and tables in the Ulysses preferences. Assign each Inline Style different start and end tags. In the text, give the images that should become figures (thus, the ones that should have "Abbildung:" in their description/title) the start and end tags of figures. Do the same for formulas and tables. When exporting, assign the figure Inline Style to the action "Figure", the formula Inline Style the action "Formula" and do the same also for tables. In this way, each type should get its own description/title.
I know this is a bit cumbersome, but this is pretty much the only way.