Device Type not populated with Server Log importer

Hi,

I am using the Server Log importer to import my nginx logs into Piwik. (using Piwik 1.12)
They look like this:
149.219.195.226 - - [03/Dec/2013:11:42:46 +0100] "GET /appserver/some/url HTTP/1.1" 200 4125 "http://some_site/url" "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:17.0) Gecko/20100101 Firefox/17.0"

All of the information seems to be imported fine into the database, but the following fields are not populated:
config_device_type, config_device_brand, config_device_model, config_os_version

When I track visits through Javascript, these values are populated fine. Unfortunately, I need to use the Server Log Importer because I need to restore old views that were not tracked with Javascript.

Can I overcome this issue using the Server Log importer?

Kind regards,
Petros