Jamil, maybe the problem you had with attenuation with the saison yeast was because your gravity was too high to begin. Aren't traditional saisons supposed to be 3 to 3.5% abv?
Jim

According to Phil Markowski in "Farmhouse Ales"the original Saisons were made for Saisonniers (Seasonal Workers) who drank them while in the field. They were accordingly low strength even down to 2.5%, typically 3-3.5%. The modern day versions are typically 4.5-6.5%.The Saison Veille Provision by Dupont is 6.5%, achieving this with an original gravity of only 1.054 because the final gravity is 1004.As far as your temp fermentation guidelines Dupont ferments at 85-95 F but some others ferment lower (Pipaix at 76F)."Farmhouse Ales" mentions the use of Brett type yeasts in the old style Saisons.I may try one simple Brett yeast in the batch I'm brewing ( my first of this style). I'm thinking that the Brett will definitely dry things out. White Labs lists the attenuation of their Saison yeast (565) at -65-75%.That is way too low to get the attenuation sought for this style.The Belgium brewers of Saison typically get 90-95% attenuation. White Labs recommends using other yeast strains to finish the job.Maybe going to the higher temperatures will do it as well.I started out my current batch at 70F and am ramping it up to 75 then 80 maybe even higher weather permitting..Phil M. recommends transfering to a secondary to avoid exposure to autolysized cells should the fermentation drag on.He recommends being patient and waiting for the gravity to go down.It is mentioned that the first generation of yeast may not be active enough so you should be prepared to add something to help it.Anyway this is a very interesting beer, I just hope it tastes good.