Install Muliti Instances on SQL 2005 cluster with the same server name

I am trying to install multi instances on my server cluster 2003 R2 Sp2. Because of the compatibility issues with my services I need to install both SQL 2000 and 2005. With 2000 I can easily specify the instance and servername. The server name can be the same, but the instance has to be different. Is this true for 2005? I have found so far that for every new instance that you create that you need to have a different virtual server name. How can you utilize the same virtual name and have multi insances

servername\$instance1

servername\$instance2

and so on

ThatGuy

I do not think this is supported as virtual server name should be unique across the network in your domain.