built_in deprecated, what to use?

[haarts]

Dear list,
I want to enable my users to translate content on a site. But I only want to display the translations specific for the site. So I am fine with all defaults already in the database. So I figured to use the built_in field to filter out all defaults. However everything put in the database automaticly has built_in set to true. This, I saw in the tickets, is a bug but won't be fixed as the built_in field is deprecated. But what is the alternative? What is the 'new' way?
Thanks for any pointers!

With kind regards,
Harm