The documentation available for customizing locators is in adequate and does not provide enough scenarios. The white paper link below was released in 2010. Several forums threads exist regarding questions or issues with user locators. It seems there are a couple of staff that are awesome and help these users yet the official support desk will not field questions related to locator content posted on the forums.
We are quickly approaching new releases and now several service packs, major and minor releases since the locators were changed in 10.0 and the 2010 documentation was made available.
Please consider fully documentating the customization of locators with examples including standards that apply to most of North America and the rest of the world as requested by the user community.