Verification of JAR signing not working on signed files with non ascII character

FULL PRODUCT VERSION :
1.6.0_07

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 5.2.3790]

EXTRA RELEVANT SYSTEM CONFIGURATION :
Windows is installed for Japanese language using Japanese fonts.

A DESCRIPTION OF THE PROBLEM :
I had a JAR that failed with JARSigningException on a Windows 2003 machine using Japanese characterset using Java Web Start 1.6:

The same JAR DID work on the same machine if Java Web Start 1.5 was used. The same JAR did also work on Windows XP machines with BOTH version 1.5 & 1.6 of Java Web Start.

I believe it was due to a filename in the JAR with non-ascii character:
stepworkbenchhelp/importing/tutorials/mapping_columns_automatically_—_the_automap_function.htm

This file was signed in the MANIFEST:MF file. However, I guess due to some characterencoding problem, it was not matched up with the actual file.

ERROR MESSAGES/STACK TRACES THAT OCCUR :
com.sun.deploy.net.JARSigningException: ¿¿¿¿ http://borg.stibo.dk/jars/STEPworkbenchHelp.jar ¿¿¿¿¿¿¿¿¿¿¿¿¿¿
at com.sun.javaws.security.SigningInfo.checkSigning(Unknown Source)
at com.sun.javaws.LaunchDownload.checkSignedResourcesHelper(Unknown Source)
at com.sun.javaws.LaunchDownload.checkSignedResources(Unknown Source)
at com.sun.javaws.Launcher.prepareLaunchFile(Unknown Source)
at com.sun.javaws.Launcher.prepareToLaunch(Unknown Source)
at com.sun.javaws.Launcher.launch(Unknown Source)
at com.sun.javaws.Main.launchApp(Unknown Source)
at com.sun.javaws.Main.continueInSecureThread(Unknown Source)
at com.sun.javaws.Main$1.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)


REPRODUCIBILITY :
This bug can be reproduced always.

CUSTOMER SUBMITTED WORKAROUND :
I have renamed the file with the non-ascII character in the JAR, that had the signing problem.
workaround:

Release Regression From : 6
The above release value was the last known release where this
bug was not reproducible. Since then there has been a regression.