Hi Jeff,
without knowing the software you're trying to control or the api commands it may require it is tough to show exactly what you need.
However, here is a simple HTTP post to tell vMix running on the local PC to do a fade transition.
ogscript.asyncPost('http://127.0.0.1:8088/api/?Function=Fade&Duration=100' , null, null);
if you require a visual reply on your panel that it has completed you can create a small function to do so.
#DashBoard