How to Create a Filte using the WDM_CSA architecture

hi
i am trying to get a control of the system audio
can anyone help me in finding how to create a filter over sysaudio and how to create a pin on that filter.
i have been fighting over this and reading a lot of DDK stuff but can;t get the implementation help.
i would be really greatfull if some one could tell me some way
to get a hold of filter and pin in the kernel mode
or how to access the audio system and control its capture and play systems.
shishir