adding a mime type to tux

hi, i was wondering if you know how to add .ppt (ms power point) as a mime type to tux.mime.types.

i assume it is just like for ms word like this:
application/msword       doc

so would it be 
application/mspowerpoint     ppt

right? please let me know the exact syntax and spelling for powerpoint if you know or a link to anywhere this is documented..
thanks so much.
chris