add media file type

Uploading files into Content > Media ..

Home > Administration > Content > choose Media tab > Add file

the Allowed file types are shown as:

jpg jpeg gif png txt doc xls pdf ppt pps odt ods odp mp3 mov m4v mp4 mpeg avi ogg wmv ico.

My question is ... how / where do I add further file types (e.g. kml and kmz) to be uploaded by dragging into window?

I have read this .. http://www.drupalgardens.com/documentation/content/custom-content-types

but I don't see where to add to the allowed file types to drag and drop for upload to Content > Media

Can kml and kmz be added ?

I have also read this and it doesn't help either... http://www.drupalgardens.com/content/types-files-upload ...i followed these directions and still can't figure out how to upload a .kml file