How to make a part of log message uppercase

[Cankut Eskin]

Hello,

I'm using AdoNetAppender to log messages. I've added
%property{log4net:HostName} conversion pattern to the message parameter.

<parameter>
      <parameterName value="@message"/>
      <dbType value="String"/>
      <size value="4000"/>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="[%property{log4net:HostName}] -
%message"/>
      </layout>
</parameter>

Output is like

[hostname] - foo bar.

But i want the output like

[HOSTNAME] - foo bar.

How can i make the hostname uppercase using conversion patterns?

Regards,

Cankut