Custom dinamical authorization by parameter

Hi all!

I am newbie in this forum. I use rich faces, webflow, and Spring security in my application, but I have faced the following problem:

I need to write custom authorization, that is support user properties based authorization. (such as: the manager of the selected object is the current user)

How could I do it with spring security?

I tried to write custom AccessDecisonManager, but I can't access any context.

Every idea is appreciated,
Thanks in advance!