I suggest the following: you need a dress box with a fitted but loose lid as the garment needs to breathe (all garments do). You need lots of white tissue - not coloured in case any colour seeps into the fabric.
Pad the floor of the box with rolled tissue then gently(two people best here) lower the dress as if folding it into the box, but onsert rolls of tissue inbetween each layer of dress and each layer of folding, if that makes sense.
Finally gently seal the top of the box with tucked in tissue.
On the day, you will need to gently touch the garment with a cool iron if any creases have occurred.
Hanging anything with beadwork is a bad idea as gravity will pull the beads free from the tulle backing over time. It wouldn't matter if the dress were to be worn next week, but lots of months is risking the beady disaster.
It looks beautiful.