SQL Express 2008 R2 - CREATE DATABASE permission denied in database 'master'

Question

I have created a setup application with SQLEXpress 2008 as a prerequisite. On test SQLExpress installs OK
after the application is installed it must create and install a database using a mixture of SMO and Scripting. I used SMO to add the current user (who is a Windows Administrator) as a Login to the SQL Express server.
Dim l As Login = New Login(srv, My.User.Name)
                l.LoginType = LoginType.WindowsUser
                l.AddToRole("sysadmin")
                l.DefaultDatabase = "MASTER"
                l.Create()
It fails on srv.CreateDatabase with error message "permission denied in database MASTER"
this thread talks about converting the server to single user mode before adding a login
http://social.msdn.microsoft.com/Forums/en-US/sqlexpress/thread/86daf5f5-d333-40b1-ae6f-0da052a96600
how is it possible to scrip this? there is no documentation i can find. 
the database must be installed in the ProgramData folder. Is there a permissions issue with this. Do I need to assign permissions to this folder somehow?
bear in mind this will be a remote install and the user expects it work flawlessly.  No manual interventions

Answer 1

if i connect to the sqlexpress instance  (local)\SQLEXPRESSS  using SQL Management Studio and try to modify the Windows User Login I get the error message:
"User does not have permission to perform this action. (Microsoft SQL Server, Error: 15247)"
how is this possible. it seems to be at an impasse. can't go forward or backward 
Now try launching Managenment Studio by right clicking on shortcut and choosing "Run As Adminitstartor".
If above works then you are running on Windows 2008 family OS (Vista, 2k8 or Win7) which has
UAC feature.
If above does not work then you really don't have permission then follow below. 
Troubleshooting: Connecting to SQL Server When System Administrators Are Locked Out
Start the instance of SQL Server in single-user mode by using either the
-m or
-f options. Any member of the computer's local Administrators group can then connect to the instance of SQL Server as a member of the
sysadmin fixed server role.
http://msdn.microsoft.com/en-us/library/dd207004.aspx
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