Hey DarknesZ -
Your big problem is going to be getting the Switch to function at all. Despite its tag in the Material Editor, it is actually known as a Static Switch because it will only exist at compile time and not at runtime. So even if it were possible to pass a Dynamic Parameter into the Switch you would not be able to change the value in Cascade.
However there is an easy replacement, use a LERP. You would just need to make sure that Cascade only every receives a hard 0 or hard 1 and you would not see the fade from one to another. In this case simple plug the Dynamic Parameter directly into the LERP’s alpha.
Thank You
Eric Ketchum