[galaxy-user] user specific access/options

Hi everybody, I am developing the application on Galaxy server. One of the requirement is to create user specific list of options. Is it possible to access somehow $__user_email__ in <options> tag or in <conditional> ?. I did not found documentation how to used cheetah in galaxy tool xml files but from files provided with galaxy, cheetah is used only in <command> and <config> tag. Is that rigth? If it can be used in any part of xml definition file it would make much easier to generate xml dynamicaly based on the $__user_email__ Does anybody have an idea how to manage this problem? Petr Novak