Hi - I was able to do something similar using the Oracle MapBuilder utility, maybe the XML syntax produced by this tool will you.
In my example I'm only displaying the STATE theme for those US States which have an abbreviation beginning with 'A%': (i.e Alabama, Alaska, Arizona, Arkansas).
<?xml version="1.0" standalone="yes"?>
<features style="C.STATES"> (STATE_ABRV like 'A%') </features>
<label column="STATE_ABRV" style="T.STATE_ABBRV"> 1 </label>
- C.STATES is a "color style" rendering the colour grey enclosed by a black border.