S3 and apache mod_proxy with basic authentication

I'd like to redirect to my S3 bucket in SSL with a basic authentication for some of my files (apk files) with the apache mod_proxy. SSL and mod_proxy perfectly work, but basic authentication is ignored.

<VirtualHost *:443>
        ServerName resources.mydomain.jp

        <FilesMatch "\.apk$">
          Order deny,allow
          SetEnvIf User-Agent ".*Android.*" allow_ag
          Options FollowSymLinks
          Allow from env=allow_ag
          Deny from all
          AuthType Basic
          AuthName "Secret Zone"
          AuthUserFile /etc/httpd/.htpasswd
          Require user xxx_customer
        </FilesMatch>


        SSLEngine on
        SSLProxyEngine on
        SSLProtocol -ALL +SSLv3 +TLSv1
        SSLCipherSuite ALL:!ADH:RC4+RSA:+HIGH:+MEDIUM:-LOW:-SSLv2:-EXP
        SSLCertificateFile conf.d/xxx.cer
        SSLCertificateKeyFile conf.d/xxx.key
        SSLCACertificateFile conf.d/xxx.cer

        ProxyPass / http://ift.tt/1Hkr0fv
        ProxyPassReverse / http://ift.tt/1Hkr0fv

    </VirtualHost>

By the way, the same "FileMatch" is used for another VirtualHost and works normally....

apache info :

$ httpd -v
Server version: Apache/2.4.12 (Amazon)
Server built:   Mar 18 2015 20:24:15

Thank you