how to use self defined IO control command to stream minidriver?

Hi:
all ,i use the ddk’s example testcap driver as my driver frame ,and i
have already complete the video part that is i can use the direct_show’s
graph edit to capture the video data.
but now in my card there should have some specific command like the
IO_CONTROL in general driver, who can tell me where should i define this
specific command ,and how to use it in direct show’s filter.
thanks a lot .