ESB Visual editor removes http-client-property in JBDS 5. How to avoid it?

Issue

I have a SOAPClient action which requires to provide the HTTP basic authentication information through a file. The only way to make it work is to edit the action like this as children of endpointUrl property:

     <property name="endpointUrl" value="http://mmw70cnc:9595/servername">
        <http-client-property name="file" value="httpclient.properties" />    
     </property>

But ESB editor removes it everytime I make changes using GUI. How to avoid it?