[Plugin: W3 Total Cache] redirect error

hi I am using google pagespeed which informed that my posts / resources are not using maxium age for various resources. Here’s the message

Setting an expiry date or a maximum age in the HTTP headers for static resources instructs the browser to load previously downloaded resources from local disk rather than over the network.

So I decided to add the following in /domainname/.htaccess file

<IfModule mod_expires.c>
    ExpiresActive on
    ExpiresByType text/css "access plus 60 days"
    ExpiresByType text/javascript "access plus 60 days"
    ExpiresByType image/ico "access plus 60 days"
    ExpiresByType image/jpg "access plus 60 days"
    ExpiresByType image/jpeg "access plus 60 days"
    ExpiresByType image/gif "access plus 60 days"
    ExpiresByType image/png "access plus 60 days"
    ExpiresByType text/css "access plus 60 days"
    ExpiresByType text/html "access plus 60 days"
</IfModule>

When I try to write this file and refresh my site, W3 Total Cache plugin overwrites the .htaccess file back to it’s original state

# BEGIN W3TC Browser Cache
<IfModule mod_deflate.c>
    <IfModule mod_headers.c>
        Header append Vary User-Agent env=!dont-vary
    </IfModule>
        AddOutputFilterByType DEFLATE text/css text/x-component application/x-javascript application/javascript text/javascript text/x-js text/html text/richtext image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon application/json
    <IfModule mod_mime.c>
        # DEFLATE by extension
        AddOutputFilter DEFLATE js css htm html xml
    </IfModule>
</IfModule>
# END W3TC Browser Cache
# BEGIN W3TC CDN
<FilesMatch "\.(ttf|ttc|otf|eot|woff|font.css)$">
<IfModule mod_headers.c>
    Header set Access-Control-Allow-Origin "*"
</IfModule>
</FilesMatch>
# END W3TC CDN
# BEGIN W3TC Page Cache core
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteRule ^(.*\/)?w3tc_rewrite_test/?$ $1?w3tc_rewrite_test=1 [L]
    RewriteCond %{HTTP:Accept-Encoding} gzip
    RewriteRule .* - [E=W3TC_ENC:_gzip]
    RewriteCond %{HTTP_COOKIE} w3tc_preview [NC]
    RewriteRule .* - [E=W3TC_PREVIEW:_preview]
    RewriteCond %{REQUEST_METHOD} !=POST
    RewriteCond %{QUERY_STRING} =""
    RewriteCond %{REQUEST_URI} \/$
    RewriteCond %{HTTP_COOKIE} !(comment_author|wp-postpass|w3tc_logged_out|wordpress_logged_in|wptouch_switch_toggle) [NC]
    RewriteCond "%{DOCUMENT_ROOT}/wp-content/cache/page_enhanced/%{HTTP_HOST}/%{REQUEST_URI}/_index%{ENV:W3TC_PREVIEW}.html%{ENV:W3TC_ENC}" -f
    RewriteRule .* "/wp-content/cache/page_enhanced/%{HTTP_HOST}/%{REQUEST_URI}/_index%{ENV:W3TC_PREVIEW}.html%{ENV:W3TC_ENC}" [L]
</IfModule>
# END W3TC Page Cache core

I am not quite sure what to do.