Finding and assigning Fsx control commands.

Hi folks. Im in the early stage of building a Vulcan bomber sim, most likely using the Iris simulations Vulcan. Since the Vulcan has no complicated systems such as FMS, i thought it would be a cheaper option as apposed to say a 737.

My question is. How do i find certain commands in the Fsx command/assignments, under the usual options for controlls. I see all the usual Fsx commands listed and my appropriate key/button assignments. But since the Vulcan has comntrols such as HP cock open engine 1 through to 4. Many of the things that i want to control within Fsx are not included in the lists. How do i find out which key is assigned to what so that i can set up these commands to an IO card?

Any help appreciated.