Hi, I've been using Netcetera (UK) for 3 years now with umbraco.
First instal via their web matrix link to umbraco - easy peasy

more recent instals, glitches to get over.

my sollution was:

• run web matix install (might well end with errors)
• create new database & a user through CP
• mannualy add connection string
  CP > file manager > "site" > wwwroot > web.config > edit
  <connectionStrings>
  <add name="umbracoDbDSN" connectionString="server=sql1096.netcetera.co.uk;database=newdbname;user id=newdbuser;password=newdbpassword" providerName="System.Data.SqlClient" />
  </connectionStrings>

• go to www.newdomain.co.uk/install/ (accept license steps etc)
• should except db connection... and your away