How to hack "the meta" to "get_post_meta" ?

Assuming you’re asking how to return instead of display any saved post meta…

You have to change the_meta() to get_post_meta(), get_post_custom() or another similar function in the code. There’s no way around it.

Your question doesn’t make a lot of sense. What is it that you’re trying to accomplish? If you absolutely cannot change the template, and you don’t like the output, then you could create a plugin to filter out the portion that you don’t like before the page is displayed.

If you don’t like coding plugins in PHP, you always have the option to use jQuery to modify the HTML. Otherwise, you’re stuck with whatever your template does or doesn’t do until you change the source code.