Lightroom :: Tethered Shoot In 5.3 With Nikon Camera

I am a mac user with 10.7 OS. I recently upgraded to LR5.3 and thought to try out the tethered shooting feature with my Nikon D300. In the ‘Tethered Capture Settings’ window it shows the naming format as a DNG file. I only import image files in their native ‘NEF’ format though I am aware of the advantages of ‘DNG’ files.Anyway I noticed the captured images were named as ‘nef’ files with its standard sidecar xmp file. Note the lower case lettering for 'nef'. I am not able to import these files to my external HD because these images were grayed out in the Import window. However if I changed the format names to upper casing, NEF, these images are visible for import.

How can I avoid the extra step of having to the change the casing of the letters and have the captured images in the tethered shoot all have the correct upper casing instead?