Using the Simple thematic mapping configuration users can change layer symbology on the fly.
The principle of the Simple thematic mapping functionality is to apply a symbology style in terms of a layer file to a specific layer of a dynamic map service.
Note: WebOffice 10 R3 does not support any customer rendering in layer files.
Note: WebOffice 10 R3 does not support implementation of joined layer files.

Simple thematic mapping configuration
Administrator may configure one or multiple symbology styles for a layer and name each of them. The user is then able to select from one of these styles in the WebOffice 10 R3 client.

Setting a layer symbology in ArcMap and saving the symbology definitions into a layer file (.lyr)