The details are easy ...remove the piston hanks, cut off the luff boltrope, sew on a new 'continuous support tape' that fits exactly to the foil groove of your new furler. This is a farily easy and straightforward job.
Are you sure your sailmaker isnt objecting to do this because this sail is 'worn out or destroyed by UV exposure, etc.' .... and simply not worth the effort? Springtime is NOT a time to expect any work from a sailmaker as most folks are expecting to have all the work they gave the sailmaker back in October, etc. to be finished by now. Sailmakers are ALWAYS OVERLOADED with work in Springtime and their long-term and repeat racing
customers will always take preference.