Sounds awesome. I never knew they used sea salt until i read it. Sounds like it's a secret recipe
if i remember correctly from a documentary that i seen about the making of the soap that its seawater that is used . ( not doubting wgat you read , just sharing what i saw ) the link below is the making of the soap , not the exact documentary that i saw .
http://www.youtube.com/watch?v=ONqF9AhLQ0s&list=TL5vJ_JI5L24s
Marseille is an elemental city. Painted in strong colors by the sun, it's full of Mediterranean smells and tastes, from the aroma of the Vieux Port fish market to the tang of bouillabaisse. Rosemary grows wild along the coast, as do olive trees, and the air along the cliffs is redolent with the fragrant maquis. One of Marseille's most famous products, soap, follows the same balance of basic beauty. For centuries, the city's famous soap makers used pure olive oil,
alkali from sea plants and sea water to create savon de Marseille, treasured for its purity and quality. Most of the savonneries are gone but the famous cubes of soap can still be found in Marseille.
http://www.nytimes.com/2005/01/23/travel/23foraging.html?pagewanted=print&position=&_r=0
hope it helps....... savon de syria and savon de Marseille are my dream to make when ever the day present itself.