thanks for this post, so I am as well busy with this issue.
The file Resources.en-us.xml contains this items as you describe. So I installed the German languages. Do I need do download Resources.de.xml somewhere?
If you want to translate the resources in German then you have two options.
1. This is the easier option. If you already have a German language as an active language the resources for the plugins should already be present. Just search for all resources that contain sevenspikes and translate them in German.
2. This option will require uninstalling and then installing a plugin again. Copy the Resources.en.xml file and name it Resources.de.xml file. Translate it in German and then when you install the plugin the resources will be added for the German language (You need to have a German language as an active language in your nopCommerce).
Please let us know if you need any help with this!