@vilas
It seams that you are mixing things. Airbus's FMS design and features don't have anything to do with design of the procedures. You can put whatever you want for ACC height, but legaly you are not allowed to accelerate before reaching missed app altitude or MSA.
As FlyingStone said, in most modern aircrafts it's not a problem to accelerate before because you will have initialy much better climb gradient then minimum required, but if something goes wrong, lawyers will blame you for sure for acting against rules