Here's what you do.
Go to hype -> preferences -> Export Scripts and open the sizmek Expor Script on finder.
Then, use whatever text editor you prefer and open up the script with it ( I recommend Sublime Text)
Cmd+F and search for "exportShouldUseExternalRuntime" And change from False to True...
Remove the # in front of "exportExternalRuntimeURL" and put the external URL you use there and it will always have the same URL for all banners every time you use that script.
I assume that should work.
If your Script looks like this
Your export option should look like this