AWSELB Cookie access from Javascript

I having problems to access the "Set-Cookie" header where AWSELB id is stored in order to set it for the subsequent requests.

I thought it was a problem with CORS configuration so i tried:

cors.headers = [
    'Access-Control-Allow-Origin' : '*',
    'Access-Control-Allow-Headers': 'origin, authorization, accept, content-type, x-requested-with, X-Auth-Token, Set-Cookie, set-cookie',
    'Access-Control-Expose-Headers': 'Set-Cookie, set-cookie'
]
cors.allow.origin.regex = '.*'
cors.expose.headers = 'Set-Cookie, set-cookie'

In the server side.

I can see all those CORS headers in the response, still when i try to getAllResponseHeaders from client side i cannot see "Set-Cookie" neither i can get specific header by name.

I am missing something?

I've check this in both Chrome and Firefox