caulking around exterior vinyl clad mull posts and jams on a door

[sphinx67a]

I recently had a new exterior door installed and after it was installed i noticed stickers on the vinyl clad mull posts that said "no caulk". these stickers were right above the sill. I asked the man who installed the door what they meant and he said "don't put caulk around the mull posts. I am confused because this really looks like a place where one should put caulking so as not to get a leak under the sill. Has anyone ever heard of this? The mull posts have a thin vinyl covering over wood. The jams have the same covering and they were not caulked either.

[Lawrence]

I would guess that the product is designed to expand and contract at that joint with changes in the elements and caulk would prevent this. what brand of door is it?

[sphinx67a]

The door and sidelites are by Masonite, but I'm guessing the rest of the door parts are by all different manufacturers because Masonite didn't recognize the mull posts. The dealer that I bought the door and had the door installed by is shady to say the least. He will not tell me where all of the door parts are from and is very uncoperative. The Mull posts may be from Endura, they said that they recognized them to be theirs but they didn't recognize the thin vinyl cladding that was put over the mull posts. So I'm in a quandry. Endura said that without caulking around the jams and the mull posts it's like a leak waiting to happen.