[Fontconfig] Help, about font size

[Jeffrey Shen]

Hi my friend,
Sorry I don't know your name.
I have a problem about fontconfig. I'm currently using XFree86 4.2.1, with
built-in Xft and fontconfig. I wanna disable anti-aliasing for SimSun font
and just for size smaller than 12 points. First I add:
<match target="font">
    <test qual="any" name="family">
        <string>SimSun</string>
    </test>
    <edit name="antialias" mode="assign">
        <bool>false</bool>
    </edit>
</match>
OK, all SimSun characters are now un-anti-aliased, next I'll add the size
constraint:
<match target="font">
    <test qual="any" name="family">
        <string>SimSun</string>
    </test>
    <test qual="any" name="size" compare="less_eq">
        <string>12</string>
    </test>
    <edit name="antialias" mode="assign">
        <bool>false</bool>
    </edit>
</match>
The result is: all SimSun characters are ANTI-ALIASED!!!
I think maybe it's because that SimSun is a TrueType font, it doesn't have X
font size property.
Did I do something wrong? Or fontconfig has to have a new property,
something like "displaysize" or "actualsize"? Please give me some advice.
Thanks a lot.

Jeffrey Shen