Hi Ivan, i think you are the same guy i answered on AG forum,
i wrote there what i think the reason for your problem, i think too thin spray cover,
need to spray well over the surface then 1 mf wiping it on , and second mf wipe it off, wiping off step very important, MF need to be soft and great cleaning ability as our BOA MF.
here is another video we did quickly few days ago to show how it done , under direct sun and hot surface even : sorry for the bad quality.
http://youtu.be/KWVIj9BeLBE