Yes you can do that and if you search “Mediacache SMIL” in the forums search bar above, you would see the accepted answer for this question:
But the very first important step is you have the src path set up properly in MediaCache to pull the mp4 file from the 3rd party server where you have it stored. Then you can connect the two using StreamPublisher as is explained in the forum post I linked above.
Go to 1:20 in this wowza tutorial where we show how to configure MediaCache first then click follow the steps to connect MediaCache with Smil in StreamPublisher
