There is a bureaucracy involved. To name a feature, you need approval from International Astronomical Union Working Gruop for Planetary System Nomenclature. No, I am not kidding.
Ah yes, the IAUWGFPSN. You don't mess with those guys. I think they have Gary Coleman on staff. He's a real hard case. Ironically, he killed a man for using the word "ironic" incorrectly.
http://planetarynames.wr.usgs.gov/