Proceed to cut slices of the nori sheet (half inch wide) and make the leaves ( i found out that the one with the squared, long stem works best).
Wet the slices in water (i used cold water, don't know if temperature changes something)
Wrap the nori slice with a spiral and insert the leaf between the wraps (don't wet the stem)
Let the stalks dry aside (you'll need to put them in the oven later)
Cut the nori sheet to form semicircular pieces
Make the roses, as in the original instructable
Wrap the base of the roses with the pieces
Put the roses in the oven (!!! careful not to make the seaweed dry too much)
When the roses are done, put the stalks in the oven to dry (leave the door open)
Put the roses on the stalks and you're done.