FIWARE - PEP Proxy configured to HTTPS

I would like to know how I configure the PEP Proxy so that I can exchange messages through HTTPS. I have an instance of Orion context broker that is accessed only after pass by the PEP Proxy. My PEP Proxy (Wilma) configuration file (config.js) has the following:

config.https = {
   enabled: true,
   cert_file: 'cert/idm.crt',
   key_file: 'cert/idm.key',
   port: 443
};

config.account_host = 'https://localhost:8000';   //account.lab.fiware.org';
config.keystone_host = 'localhost'; //'cloud.lab.fiware.org';
config.keystone_port = 5000; //4731;

config.app_host = 'https://orion'; //'localhost';
config.app_port = ''; //Nginx is configured to redirect to port 1026
// Use true if the app server listens in https
config.app_ssl = true;

config.username = 'pep_proxy_credential_obtained_at_portal';
config.password = 'password_obtained_at_portal';

I have also HTTPS to HTTP (Nginx configured as reverse proxy) so that my requests directly sent to Orion are secure. The HTTPS is working only without PEP Proxy flow. When I insert the authorization/authentication flow, I am facing problems, because the PEP Proxy does not handle with the SSL certificate. Here is the Nginx configuration:

location / {
    proxy_set_header        Host $host;
    proxy_set_header        X-Real-IP $remote_addr;
    proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header        X-Forwarded-Proto $scheme;

    # Fix the “It appears that your reverse proxy set up is broken" error.
    proxy_pass          http://orion:1026;
    proxy_read_timeout  90;
    proxy_redirect      http://orion:1026 https://orion;
}

I want to integrate what I have in a way I can communicate with Orion only by HTTPS, including the PEP Proxy flow. I've searched but I did not find nothing useful related to HTTPS configuration in PEP Proxy.

EDIT: There is an error when the PEP Proxy redirects to the application:

2017-01-17 20:52:55.544  - INFO: Server - Success authenticating PEP proxy. 
Proxy Auth-token:  d7ec08edd87d43418edfd558df26f427
2017-01-17 20:53:49.450  - INFO: IDM-Client - Checking token with IDM...
2017-01-17 20:53:49.508  - INFO: Root - Access-token OK. Redirecting to app...
Refused to set unsafe header "accept-encoding"
Refused to set unsafe header "content-length"

The error presented by the application is:

('Connection aborted.', BadStatusLine('HTTP/1.1 0 unknown\r\n',))

The problem was the https at configuration:

config.app_host = 'https://orion';

I had to debug to find this. The PEP Proxy Wilma adds the protocol (http or https) to the application host configured. The correct is to configure without the protocol:

config.app_host = 'orion';

Maybe this observation can be added to Wilma documentation in order to avoid errors like mine.