Another Cell issue - How do I create this?

I'm completely stumped by this just now. I'm trying to create a cell of a carpet tile which comprises of 600x600mm square that has an outline fill colour and a dropped stucco pattern on top to give it a bit of texture. When I place the cell as an associative pattern all I get is a mass fill colour. If turn off fill I can see the individual tile outlines but the stucco texture never appears. I've tried using element priority but it still fails. I can place the cell as a normal cell and it appears correctly but fails as a pattern.

Does anyone know what is going on and how to achieve this?