[support] D6 hook_menu

I have looked through the docs about this but I don't understand how this works. I want to send URLs of the type foo/% and also foo/%/% to the same function, but it seems to me that I must use $items['foo/%'] = array( and $items['foo/%/%'] = array( Using just one or the other is failing for me. Am I missing something or is this how it must be done? Two different items? Thanks.