Is there one? By default, CTRL+D is bound to Edit.GotoDefinition, which is VS's implementation and it just spins looking for it. Whereas Shift+Alt+G shows a nice VA drop down of where it is (so VA does know where it is!).
IDE tools menu -> Options -> Environment -> Keyboard
and select the command "VAssistX.GoToImplementation" in the list, and then set Ctrl-D for the text editor as the key binding.
I am not following why you are confused. VA is adding its own Alt-g command, but we have not replaced or disabled the built in IDE commands. Our Alt-g command uses our symbol database and our parser. The IDE command uses the IDE parser. There will be times when the IDE does a better job, and times when we do a better job.
As far as I am aware the IDE does not offer the Goto Related command, so that is just from VA.