mime editor


I use custom environment (no gnome, no kde...)
i want to edit MIME, so that apps that i use can use this data.

For example, i want to be able to open transmission torrent file directory with rox. Currently it ain't possible.

therefore i want to know a name of good mime editor and/or where can i edit this data on my system (perhaps with text editor).

I've searched google, but didn't find anything much of use