All you are doing is creating an actor at the origin point of the launch missile effect, correct? (AKA the ghost academy). Simply have the "flash" animation play at the ghost academy when you need it to. At this point you are using site ops on an attachment, which is a little bit different. Make sure that you have the host set to the correct alias or reference, and then you are good to go.
And because I will be showing STEP BY STEP how to make an uberlisk for tonight's DATA MONDAY, starting at 7:00 GMT - 5. Some things have changes since this tutorial was posted, but I will cover those. Expect some simple site operations first, for example a zergling riding an overlord before we get into the overlord. This is some fairly complex stuff, but I feel it will really help a lot of you with your maps!