How to set a not_analyzed field with Kibana or Log4net -

I have the following setup: I log my logs with log4net and ElasticSearch and then I look for the logs and make all my searches with Kibana. In the webconfig I have:

<appender name="ElasticSearchAppender" type="log4net.ElasticSearch.ElasticSearchAppender, log4net.ElasticSearch">
  <layout type="log4net.Layout.PatternLayout,log4net">
 <param name="ConversionPattern" value="%date - %level - %message %property{mstimeload} %property{applicationid} %property{applicationid} %property{page} 
   %property{ipclient} %property{browser} %property{browsersignature} %property{appversion} %property{sessionuniquecodetag} %property{globalcountertailsloaded} 
   %property{ipserveraddress} %newline" />
  <connectionString value="Server=;Index=arcodalog;Port=9200;"/>
  <lossy value="false" />
  <bufferSize value="100" />
  <evaluator type="log4net.Core.LevelEvaluator">
    <threshold value="INFO"/> <!-- INFO: everything, WARN: all errors, ERROR: some errors-->
  <level value="ALL"/>
    <appender-ref ref="ElasticSearchAppender" />

As you can see I have many fields that I have created specifically for my problem. The thing is that in this way if I want to make a graph with the Term "page" in Kibana it splits the words and does not take the entire string as a Term:

As you can see in the graph the terms are "al07", "aspx" and so on.. Instead I want to have a graph with e.g. /AL07/mypage.aspx. I read that the problem is that the field is "analyzed" and it should be not-analyzed instead. If you go in Settings in Kibana it is written that in order to change the field types one should use ElasticSearch Mapping and the following link is given Mapping. With the extesion Sense of Chrome I have created a new index with the correct mapping and I have added "not-analyzed" for the fields that I wanted (like "page"). The problem now is that I don't know how to access to this fields from C# side. Before I did like this:

 log4net.ThreadContext.Properties["sessionuniquecodetag"] = sessionuniquecodetag;
 log4net.ThreadContext.Properties["applicationid"] = applicationid;

But now this fields are not in Properties anymore.. Do you know a solution to this problem?