String[] parametri = {username};
MapLookup.setMainArguments(parametri);

<SMTP name="Mailer" subject="${sys:logPath} - ${map:0}" to="${receipients}"
        from="${from}" smtpHost="${smtpHost}" smtpPort="${smtpPort}"
        smtpProtocol="${smtpProtocol}" smtpUsername="${smtpUser}"
        smtpPassword="${smtpPassword}" smtpDebug="false" bufferSize="200"
        ignoreExceptions="false">
    </SMTP>

<SMTPx name="ErrorMail" smtpHost="mailer.xxxx.de" smtpPort="25"
        from="your name <noReply@xxx.de>"  to="${errorEmailAddresses}"
        subject="[PROJECT-ID, ${hostName}, ${web:contextPath}] %p: %c{1} - %m%notEmpty{ =>%ex{short})}"
        subjectWithLayout="true"  bufferSize="5"
        burstSummarizingSeconds="300" bsCountInSubject="S" bsMessageMaskDigits="true"
        bsExceptionOrigin="true" >
    <PatternLayout pattern="-- %d  %p  %c [%.20t,%x]  %m%n" charset="UTF-8" />      <!-- SMTP uses fixed charset for message -->
</SMTPx>
<Async name="AsyncErrorMail" blocking="false" errorRef="Console">
    <AppenderRef ref="ErrorMail"/>
</Async>