[vCenter 4.0] Reinstalling vCenter and Nexus 1000

Hi,

We are planning to migrate our vCenter and Update Manager databases from SQL Express 2005 to SQL 2008. Mostly because our infrastructure is getting bigger and Express has its limits. While the current SQL Express 2005 databases are located on the vCenter VM, the SQL 2008 instance is Standard SP1 and clustered on other physical servers.

It is a migration, not a reinstallation. We are keeping the current database, only moving it elsewhere.

While searching for an official procedure to perform the migration, I've come accross KB1028601, which explains how to migrate the database as I want to. To be honest, I've done this in the past at my previous job on a different environment. Although it was on 4.1 instead of 4.0, I migrated from SQL Exp 2005 to SQL 2008.

My issue, and mostly the main reason why I am creating this topic, is that my current environment has a Nexus 1000 while my previous job did not. And to be brutely honest, I know nothing of this beast, other than configuring its ports in the vSphere Client UI. I don't know how it works on the backend, so I don't know how playing with vCenter Server services will affect it. Here are some questions that I am hoping you can answer :

1. Because I need to stop the vCenter services, will this affects the Nexus 1000 operations ?
   
2. In KB1028601, it is asked to reinstall vCenter Server once the database has been restored on the SQL 2008 instance. Do I need to do something with the Nexus 1000 ? I know there are some links between the Nexus 1000 and the vCenter Server, so my guess is that I have to do something after reinstalling vCenter.
   
3. Where can I get good information about the Nexus 1000 ? Understanding how it works, how it is connected in a VMware environment...possibly a manual other than searching through Google.
   
4. Do vCenter supports SQL Clustering ? I will connect the DSN using the clustered instance name, but I know some systems/applications don't really like when SQL is failing to another node.
   
5. Since we are running vCenter on Windows 2008 R2, can we create a 64-bits DSN in vSphere 4.0 ? Doing so will ensure that I won't need to recreate the DSN if I upgrade my vCenter to 4.1 or 5.x in the future.
   

Thank you,

Guillaume.