ACE reports: how obtain some info dynamically ?

Hi, We have some ace reports that we support. But we don't have much doc. on ACE and it doesn't tell anything on what I need to know. Can ACE obtain some info. while running e.g. reading an an environment var. So far I have only found that it can take arguments and that is one way of doing it, but I want to be able to get info from environment or file etc. Can somebody tell me how it's done in ACE or if you can, send a sample of code that does these kind of things. Thanks for any info. Please cc me in your reply. AH