Grails 1.3.7 UTF-8 issue when deployed on Tomcat6

[seanG]

Hi,
I am trying to deploy an application created in 1.3.7 that recieves a notification from a desktop app and depending on the user's language, will send a language-specific 'thank you' email. The emails are created from templates using javamail MimeMessageHelper like so:

MimeMessageHelper helper = new MimeMessageHelper(message, true, "UTF-8");
            helper.setFrom(new InternetAddress(config.td.mail.from.email, config.td.mail.from.text))
            helper.setTo((mailDetails.to) as String)
            helper.setSubject(config.td.mail.from.regSubject)
            helper.setText(buildRegBody(mailTemplate, mailDetails), true)

The actual mailTemplate files are all encoded in UTF-8. When running the app locally the emails are sent out without any error but upon deployment to Tomcat any international characters in the text of the email are replaced with: �������. I have had similar problems when writing international characters to a MySQL database with correct UTF-8 collation.

My config file includes the lines:

grails.views.default.codec = "none"
    grails.views.gsp.encoding = "UTF-8"
    grails.converters.encoding = "UTF-8"

I tried the following to no avail:
Added UTF-8 encoding statements to connector elements in Tomcat server xml
Made sure the charEncodingFilter is first in the chain in web.xml
Created my production war using the argument: '-Dfile.encoding=UTF-8 war'

I have run out of ideas - any help or suggestions would be greatly appreciated.
Thanks

-Sean