Can't give you the name of a specific SA, but maybe this bit of general advice will help you:
Try and speak a little french and never forget to say bonjour if you enter the store, even if to no one in particular. I know, it sounds a bit silly, but it is a vital part of french politesse and the absence WILL be noticed.
It is also a very good idea to say 'bonjour monsieur' or 'bonjour madame' when you approch someone or you get approached.
This applies not just to Hermes stores, but to all shops, restaurants and hotels, all over France.
When the french feel they have not been treated with respect, they can be extremly difficult and unhelpful in return.
But if you follow their basic rule of etiquette, you'll be amazed, how far it will get you! They will be happy to go to any length to make you happy, bending a rule or two on the way.
Good luck!