You need to change pattern-formatter value in logging subsystem in your standalone configuration. E.g.
<periodic-rotating-file-handler name="FILE" autoflush="true">
<formatter>
<pattern-formatter pattern="%d{dd.MM - HH:mm:ss,SSS} %-5p [%c] (%t) %s%E%n"/>
</formatter>
<file relative-to="jboss.server.log.dir" path="server.log"/>
<suffix value=".yyyy-MM-dd"/>
<append value="true"/>
</periodic-rotating-file-handler>