Edit server/all/conf/log4j.xml and add the following to generate DEBUG output to server/all/log/seam.log file

<appender name="SEAM" class="org.jboss.logging.appender.RollingFileAppender">
 <errorHandler class="org.jboss.logging.util.OnlyOnceErrorHandler"/>
 <param name="File" value="${jboss.server.home.dir}/log/seam.log"/>
 <param name="Append" value="false"/>
 <param name="MaxFileSize" value="500KB"/>
 <param name="MaxBackupIndex" value="1"/>
 <layout class="org.apache.log4j.PatternLayout">
 <param name="ConversionPattern" value="%d %-5p [%c] %m%n"/>
 </layout>
 </appender>

 <category name="org.jboss.seam">
 <priority value="DEBUG" />
 <appender-ref ref="SEAM"/>
 </category>