You can make skyboxes with TERRAGEN (free DL)http://www.planetside.co.uk/terragen/downloads/halcyon33/tginstall0943.msi
and it will also make terrain files you can import into NL teraformer. Just make sure you set the size to 129x129 or it will clip your environment. You'll also need the skyboxer plugin from Tia.
http://www.gravimetricstudios.com/downl ... 0_full.zip
Hope that helps! [:D]