Overlays can't be applied to moving objects, and you probably don't want to use this icon on a door that never opens (since its intended use is for doors that start closed but will open later).
If you need a door that's too large to fit this texture without tiling, you can clip the door into multiple brushes and apply the normal door texture on the spots that shouldn't have the icon, as such. Hope this helps!
Well, I don't really want to argue but AFAIK decals can.
Also I do know what can be done with brushes in Source, hope it didn't sound that harshly.
Thanks for the answer anyway.
You can apply info_decals to brush entities in Hammer, but it will cause a 'bad inline model error' for some clients, crashing them to desktop when the map loads. So don't do it.
Also there's a difference between decals and overlays. Decals are things like blood and bullet holes and sprays, and while you can technically place decals in Hammer, they tend to behave oddly; that's why Valve invented overlays.
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