A user reported the following:
Elster Online is a tax site which is using a software certificate. The certificate is stored in a file on the Mac and you open it via the applet. If there is an umlaut in the name of the certificate the applet will not see the file. Older Java versions supplied by Apple do not have this problem."
User agent string: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:14.0) Gecko/20100101 Firefox/14.0.1