Entryway Systems Location

Context: The vestibule of our commercial building has entry/exit portals; but only leads users to an unenclosed (shell-like, meaning walls on two sides and two big openings to pass thru, and a trellised roof) space. The actual entry to the building (airconditioned and fully enclosed), is from sliding doors within the vestibule. I placed the 10ft long entry mat after the sliding doors and within the enclosed space as this is how I understood the LEED intent. However, I was challenged that it should be within the vestibule area. I believe this defeats the purpose of LEED as the entry mat will be exposed to all the elements and will collect pollutants which people might even bring inside the building. Question: Should I put the entryway before the sliding doors or after? Since the portal opening might be considered to be the "regularly used exterior entrance" as stipulated in the credit. Thank you!