Depends on the version of OpenACS. These are parameters in acs-subsite for 5.7 and possibly 5.6
if you are referring to the path to the form style in the formtemplate tag, you should be able to refer to the full path relative to the installation directory ie:
formtemplate style="/packages/packagekey/lib/form-style"
if you just want to point to the style for a particular form.
In addition on openacs 5.6 or 5.7 you can create a new package that inherits from acs-subsite and customize that and store your custom code in there.
