Silent Install of SQL Server Express 2012 from Inno Setup

I am trying to install SQL Server Express 2012 silently from my application installer created using Inno Setup. When running the following command from the command line, SQL Server Express 2012 is installed as I want only showing progress of the install but not allowing the user to enter any input.

Command line command that works:

C:\Users\Jason\Desktop>SQLEXPR_x86_ENU.exe /ACTION=Install /INSTANCENAME=MYINSTANCE /INSTANCEID=MYINSTANCE /QS /HIDECONSOLE /INDICATEPROGRESS="False" /IAcceptSQLServerLicenseTerms /SQLSVCACCOUNT="NT AUTHORITY\NETWORK SERVICE" /SQLSYSADMINACCOUNTS="builtin\administrators" /SKIPRULES="RebootRequiredCheck"

In order to do this from my Inno Setup script I have the following code:

Exec(installName,
  '/ACTION=Install /INSTANCENAME=MYINSTANCE /INSTANCEID=MYINSTANCE /QS /HIDECONSOLE /INDICATEPROGRESS="False" /IAcceptSQLServerLicenseTerms /SQLSVCACCOUNT="NT AUTHORITY\NETWORK SERVICE" /SQLSYSADMINACCOUNTS="builtin\administrators" /SKIPRULES="RebootRequiredCheck"',
  '',
  SW_SHOW,
  ewWaitUntilTerminated,
  ResultCode);

where installName = SQLEXPR_x86_ENU.exe

When run from the Installer the SQL Server Express 2012 installer starts but after the first information dialog it then shows the SQL Server Installation Center window and the user has to select the type of installation before the installer continues. They also have to agree to the license agreement which was not required when running directly from the command line.

Any ideas on how to run the installer silently from Inno Setup?