I''m using this in my fonts.conf; it fixes problems with
opera and news.zdnet.co.uk for me (on LFS 4.1)..
<match target="pattern">
<test qual="any" name="family">
<string>ms sans serif</string>
</test>
<edit name="family" mode="assign">
<string>sans-serif</string>
</edit>
</match>
EMH