How to make custom fb for floating social plugin with HTML 5


I want to replace the existing facebook plugin, with my own "facebook share button" code.
Mostly because the iframe version is not nice to use (fixed width, problem with multi language/design). Embedding the HTML5 FB code as custom code in the floating social plugin works well, but I can only hard-code the used URL.
Nevertheless, I would like to be able to refer to the current blog page. But PHP code is not interpreted in that custom code.
Is there a way to do that? A special keyword to refer the current blog page maybe ?