UnsupportedDataTypeException when enabling SMTPAppender in log4j in JBoss Fuse

Issue

• Configured instance of JBoss Fuse to send emails using the following log4j appender configuration in /FUSE_HOME/etc/org.ops4j.pax.logging.cfg:

#Root logger
log4j.rootLogger=INFO, out, osgi:VmLogAppender, email
   ...
# SMTPAppender (for emailing errors)
log4j.appender.email=org.apache.log4j.net.SMTPAppender
log4j.appender.email.SMTPHost=smtp.example.com
log4j.appender.email.From=Scott's Development JBoss Fuse ESB Instance <fuse@fusesource.com>
log4j.appender.email.To=Me <me@fusesource.com>
log4j.appender.email.layout=org.apache.log4j.PatternLayout
log4j.appender.email.layout.ConversionPattern=%m
log4j.appender.email.bufferSize=512

When the logger goes to send an email due to an error, I get this stacktrace in the Fuse console:

log4j:ERROR Error occured while sending e-mail notification.
javax.mail.MessagingException: IOException while sending message;
  nested exception is:
    javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/mixed;
    boundary="----=_Part_0_402994790.1374686165243"
    at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1177)
    at javax.mail.Transport.send0(Transport.java:195)
    at javax.mail.Transport.send(Transport.java:124)
    at org.apache.log4j.net.SMTPAppender.sendBuffer(SMTPAppender.java:416)
    at org.apache.log4j.net.SMTPAppender.append(SMTPAppender.java:256)
    at org.apache.log4j.AppenderSkeleton.doAppend(AppenderSkeleton.java:251)
    at org.apache.log4j.helpers.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:66)
    at org.apache.log4j.Category.callAppenders(Category.java:193)
    at org.apache.log4j.Category.forcedLog(Category.java:365)
    at org.apache.log4j.Category.log(Category.java:772)
    at org.ops4j.pax.logging.service.internal.PaxLoggerImpl.error(PaxLoggerImpl.java:159)
    at org.ops4j.pax.logging.internal.TrackingLogger.error(TrackingLogger.java:96)
    at org.ops4j.pax.logging.slf4j.Slf4jLogger.error(Slf4jLogger.java:838)
    at org.apache.karaf.features.internal.FeaturesServiceImpl.installBundleIfNeeded(FeaturesServiceImpl.java:760)
    at org.apache.karaf.features.internal.FeaturesServiceImpl.doInstallFeature(FeaturesServiceImpl.java:586)
    at org.apache.karaf.features.internal.FeaturesServiceImpl.doInstallFeature(FeaturesServiceImpl.java:563)
    at org.apache.karaf.features.internal.FeaturesServiceImpl.installFeatures(FeaturesServiceImpl.java:399)
    at org.apache.karaf.features.internal.FeaturesServiceImpl.installFeature(FeaturesServiceImpl.java:387)
    at org.apache.karaf.features.internal.FeaturesServiceImpl.installFeature(FeaturesServiceImpl.java:383)
    at org.apache.karaf.features.command.InstallFeatureCommand.doExecute(InstallFeatureCommand.java:62)
    at org.apache.karaf.features.command.FeaturesCommandSupport.doExecute(FeaturesCommandSupport.java:41)
    at org.apache.karaf.shell.console.OsgiCommandSupport.execute(OsgiCommandSupport.java:38)
    at org.apache.felix.gogo.commands.basic.AbstractCommand.execute(AbstractCommand.java:35)
    at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:78)
    at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:474)
    at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:400)
    at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)
    at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:183)
    at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:120)
    at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:89)
    at org.apache.karaf.shell.console.jline.Console.run(Console.java:176)
    at org.apache.karaf.shell.console.jline.DelayedStarted.run(DelayedStarted.java:61)
Caused by: javax.activation.UnsupportedDataTypeException: no object DCH for MIME type multipart/mixed;
    boundary="----=_Part_0_402994790.1374686165243"
    at javax.activation.ObjectDataContentHandler.writeTo(DataHandler.java:877)
    at javax.activation.DataHandler.writeTo(DataHandler.java:302)
    at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1485)
    at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1773)
    at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:1121)
    ... 31 more