Alas I do not have a macbook or a pro
But from what I hear....
you can use a MacBook (regular) charger with the pro...and it knows not to try and charge the battery, just provide power...then if you sleep it, it will charge the battery.
However, if you use the regular pro adaptor it will try and do both, which doesnt work and the battery actually drains. So you have to remove the battery when using the inverter.