My module's field isn't showing up

i'm trying to add a field and have implemented hook_field_info(), hook_field_schema(), hook_field_validate(), hook_field_is_empty(), hook_field_formatter_info(), and hook_field_formatter_view(). i'm using the options_buttons widget so i didn't think i'd need to implement either hook_field_widget_info() or hook_field_widget_form()

for some reason my field never shows up on the manage fields page. the odd thing is that i can create an instance and add it to a content type via code and don't see to have any problems. i just can't get it to show up in the field ui.

any ideas what i'm doing wrong? i'm looking at the field_example.module as a reference but don't see anything wrong other than missing those two functions. do i tried adding those functions and just returning empty arrays but that doesn't seem to work either.