For V3 Lite, this download will be from update center, but of now, this feature is not there yet. We are still relying on the location specified in domain.xml to download the war file.
For now, here is the workaround for you:
Option 1:
1. install GlassFish v3 express (trunk) b12
2. before access Admin GUI, edit glassfish/domains/domain1/config/domain.xml
3. change this line:
<property name="adminConsoleDownloadLocation"
value="http://download.java.net/glassfish/v3-tp2/admingui/gfv3-preview2-final-admingui.war"/>
to
<property name="adminConsoleDownloadLocation"
value="http://wiki.glassfish.java.net/attach/GlassFishV3AdminConsole/admingui-v3-express-b12.war"/>
and you can access console by going to http://localhost:8080/admin
It will download the correct version for you.
Option 2:
1. download http://wiki.glassfish.java.net/attach/GlassFishV3AdminConsole/admingui-v3-express-b12.war
2. rename it to admingui.war
2. do "asadmin deploy admingui.war"
4. access it by going to http://localhost:8080/admingui\\