Use Apache as SSL offloader

Hello together,

i use Playsms in my internal LAN without SSL now i want to use Apache as SSL offloader to make it accesable from External Internet.

But it wont work correctly … styles are not loaded because the adress point to http not https when i look at the website sourcecode from External

I try to set the https env in Apache config but this wont work. When i enable the https option in config.php then ssl will work but the non SSL connection wont
work anymore.

Here is my reverse and playsms server config:

Reverse:

SSLEngine on
ProxyRequests Off
RequestHeader set X-Forwarded-Proto "https"
SSLProxyEngine on
SSLProtocol all -SSLv3 -TLSv1.1
SSLHonorCipherOrder On
SSLCompression off
SSLCipherSuite "HIGH:!aNULL:!MD5:!3DES:!CAMELLIA"
SSLCertificateFile xxx.xxx.xxx
SSLCertificateKeyFile xxx.xxx.xxx
ServerName xxx.xxx.xxx
ServerAlias xxx.xxx.xxx
ErrorLog /var/log/apache2/xxx.xxx.xxx.log
CustomLog /var/log/apache2/xxx.xxx.xxx.log combined
Header always set Strict-Transport-Security "max-age=31556926"
ProxyPreserveHost On
Redirect permanent / h_ttp://192.IP/
ProxyPass / h_ttp://192.IP/
ProxyPassReverse / h_ttp://192.IP/
VirtualHost

Playsms:

    ServerAdmin webmaster@localhost

    DocumentRoot /var/www/html
    <Directory />
            Options FollowSymLinks
            AllowOverride None
    </Directory>
    <Directory /var/www/html>
            Options Indexes FollowSymLinks MultiViews
            # To make wordpress .htaccess work
            AllowOverride FileInfo
            Order allow,deny
            allow from all
    </Directory>

    ScriptAlias /cgi-bin/ /usr/lib/cgi-bin/
    <Directory "/usr/lib/cgi-bin">
            AllowOverride None
            Options +ExecCGI -MultiViews +SymLinksIfOwnerMatch
            Order allow,deny
            Allow from all
    </Directory>

    ErrorLog ${APACHE_LOG_DIR}/error.log

    # Possible values include: debug, info, notice, warn, error, crit,
    # alert, emerg.
    LogLevel warn

    CustomLog ${APACHE_LOG_DIR}/access.log combined

#
# Set HTTPS environment variable if we came in over secure
#  channel.
SetEnvIf x-forwarded-proto https HTTPS=on

Can someone help me?
Greetz from Germany