How to override the value of solr.jetty.request.header.size

How I can override the value of solr.jetty.request.header.size in the ext-commerce/solrserver/resources/solr/server/etc/jetty.xml?

 <Set name="secureScheme">https</Set>
 <Set name="securePort"><Property name="solr.jetty.secure.port" default="8443" /></Set>
 <Set name="outputBufferSize"><Property name="solr.jetty.output.buffer.size" default="32768" /></Set>
 <Set name="outputAggregationSize"><Property name="solr.jetty.output.aggregation.size" default="8192" /></Set>
 <Set name="requestHeaderSize"><Property name="solr.jetty.request.header.size" default="819200" /></Set>
 <Set name="responseHeaderSize"><Property name="solr.jetty.response.header.size" default="8192" /></Set>
 <Set name="sendServerVersion"><Property name="solr.jetty.send.server.version" default="false" /></Set>
 <Set name="sendDateHeader"><Property name="solr.jetty.send.date.header" default="false" /></Set>
 <Set name="headerCacheSize"><Property name="solr.jetty.header.cache.size" default="512" /></Set>
 <Set name="delayDispatchUntilContent"><Property name="solr.jetty.delayDispatchUntilContent" default="false"/></Set>
 <!-- Uncomment to enable handling of X-Forwarded- style headers
 <Call name="addCustomizer">
   <Arg><New class="org.ee.jetty.server.ForwardedRequestCustomizer"/></Arg>
 </Call>
 -->