Formatting attributes when converting from an ArcGIS dataset to KML

Have a look at the KMLStyler and the KMLPropertySetter transformers. You can also take the safety catch off and play with setting the kml_ prefixed format attributes.    http://fmepedia.safe.com/articles/FAQ/What-s-the-difference-between-user-attributes-and-format-attributes   http://fmepedia.safe.com/articles/How_To/How-Do-I-Set-a-Format-Attribute   You might find the KML tutorial useful also:   http://www.safe.com/learning/training/on-demand/tutorials/#kmltutorial

I have done this for a single featureclass that had heap of category symbologies

 

 

I use some vba (if you have a vba license in arcmap for version 10 +) that gets the polygon fill colours for a featureclass in a mxd and the associated attribute and puts into a csv.

 

 

I then featuremerge that csv with the features in FME and use that value to assign to the fme_color for each feature.

 

 

Works really well. Would this could be useful for you? 

I would say SchemaMapper might be good to have a look at to map the attribute-values from ArcGIS to KML-specific attribute-values. If you do the opposite (from KML) I think FME "translates" some KML-format-colors/settings to FME-colors/settings - so they are "automatically" translated to output-formats that supports coloring (MapInfo?).