Yes, so what I'm basically doing is trying to copy exactly how the 'quote' button is implemented, except for what that button does.
In the postbit_classic template:
Example sub-template, postbit_quote :
So it's using these members of $post, such as $post['button_quote']. They are in turn populated by "eval"ing templates in functions_post.php.
E.g.:
So I'm populating my $post['button_cheese_A'] with
, in a function added with add_hook("postbit"...
That "cheese_postbit_A" template is being evaluated OK if I hard-code the text. If I try to use my lang-> variables, which are in global.lang.php just the same as the 'button_quote' ones, it just goes blank.