seperate tracking code fos sub site using Google Analytics +

i have Google Analytics + installed at the top level of WPMU and would like to use a separate code for one sub site rather than the 'global' tracking code that is set in the WMPU network admin/settings.

specifically i want a single/separate tracking code for a single site, i've already set up GA as a separate report for the site in question. but the outputted code does not show the new tracking id, it shows the global tracking id.

individual tracking code = UA-57539543-1
global tracking code = UA-51864537-1

if you view the source code of the individual site you will see both codes
sub site:

<script type="text/javascript">
var _gaq = _gaq || [];
_gaq.push(['_setAccount', 'UA-51864537-1']);
_gaq.push(['_setDomainName', 'none']);
_gaq.push(['_setAllowLinker', true]);
_gaq.push(['_setAllowHash', false]);
(function() {
var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
ga.src = ('https:' == document.location.protocol ? 'https://' : 'http://') + '';
var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);

(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),

gaplusu('create', 'UA-51864537-1', 'auto', {'allowLinker': true});
gaplusu('send', 'pageview');

gaplusu('create', 'UA-57539543-1', 'auto', {'name': 'single'});
gaplusu('single.send', 'pageview');