Binding template tag expressions in blocktrans statements

The custom shipping templates of the demo site contains template tags within the {% transblock %} tag which does not work. Check out the live demo site http://demo.oscar.tangentlabs.co.uk/checkout/shipping-method/ to see for yourself. Screenshot:

![oscar-demo-site-template-tag](https://f.cloud.github.com/assets/3015394/1431893/64dc71d8-40d6-11e3-813b-7781798a49f8.png)

Piping the variables towards template tags within the {% blocktrans %} works, as explained here:
https://docs.djangoproject.com/en/dev/topics/i18n/translation/#std:templatetag-blocktrans