Parametrizing file names with start date of process

[Laurent Hasson]

Hello,

I'd like to parametrize my log file names with the start date of the process. 
This makes it easier for us to see after the facts in the logs if a server was 
restarted etc...

The approach I took was the following:
<Properties>
  <Property name="log-path">C:\CAPSICO\_Stand_Alone_Runtime_\logs\</Property>
  <Property name="now">%d{yyyy-MM-dd}</Property>
</Properties>
<Appenders>
  <RollingFile name="FILES" fileName="${log-path}/capsico.%{now}.log" 
filePattern="${log-path}/capsico. %{now}.%i.log.gz">
    <PatternLayout>
      <pattern>%d{MMdd.HHmmss.SSS}#%-3t %level{length=1} %15.15c{1}|  
%m%ex{20}%n</pattern>
    </PatternLayout>
    <Policies>
      <SizeBasedTriggeringPolicy size="100 MB" />
    </Policies>
    <DefaultRolloverStrategy max="99999" compressionLevel="9"/>
  </RollingFile>
</Appenders>

My thinking is that ${now} would be resolved when the system starts, and then I 
could use the value in the file names. But the filenames print '${now}' 
directly.

Any help would be much appreciated.

Thank you,
Laurent.