It's probably a little bit exaggerated to modify keymap to perform this action. I'd rather use the plugin Quickbutton (not to be mistaken with Multiquickbutton).
Instead, I edited keymap to get rid of the annoying strange assignment to P+/P- to bouquets (that I find very, very uncomfy and annoying) and I swapped its assignment to LEFT/RIGHT, although after every software update I have to replace again my keymap because the update replaces mine with the original.