ess leave request

hi friends

am working in ESS leave request. i want some material to do workflow for ESS leave request. my scenerio is that when ever an employee clicks is leave request from portal workflow has to trigger. how to do this. and transaction swfvisu what is does. how r link with workflow and swfvisu t-code. I have used only BOR objects. but for this i need to use ABAP object. how to go. Every body give me a try.

Regards

vijay