periodic-rotating-file-handler rotate server.log only with started app-server at midnight

first: behavior in jboss-5.1.GA:
+ not running over night
+ starting next day:
a) older server.log renamed to server.log.yyyy-MM-dd
b) new server.log created

current behavior in jboss-7.1.0.Final:
+ not running over night
+ starting next day:
a) older server.log used, not renamed, new enries append

-> expected behavior was like jboss-5.1.

<append value="false"/> doesn't help; same server.log, older entries deleted.
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log-config in jboss-5.1.GA

<appender name="FILE" class="org.jboss.logging.appender.DailyRollingFileAppender">
<errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
<param name="File" value="${jboss.server.log.dir}/server.log"/>
<param name="Append" value="true"/>
<!-- Rollover at midnight each day -->
<param name="DatePattern" value="'.'yyyy-MM-dd"/>
</appender>