argument "breaks" in plotHeatmap function for negative values

plotHeatmap function is usually used with expression data (so positive values). In this case, argument "breaks" works great. However, I would like to use plotHeatmap function on normalized values (from zinbwave) which are positive and negative. In that case, argument "breaks" does not work great.

Fanny, I'm sorry I left this hanging. If you can stretch your memory back, what do you mean it doesn't work great? Do you get an error? Or just that you don't like what it does?

If you have code or examples, that would help.