ShellExecute ignores ShowCmd setting with IE 7

I am using ShellExecute to launch a browser in a web page, however it appears to totally ignore the nShowCmd parameter. Below are the declarations I am using:

If I pass another file - for example a text file - then the parameter is obeyed - minimize, hide etc - but if I pass a URL the browser always displays full screen with focus. I want to start the browser either minimized or hidden - Does anyone know how to get this to work?

Private Declare Function ShellExecute Lib _
     "shell32.dll" Alias "ShellExecuteA" _
     (ByVal hWnd As Long, ByVal lpOperation _
     As String, ByVal lpFile As String, ByVal _
     lpParameters As String, ByVal lpDirectory _
     As String, ByVal nShowCmd As Long) As Long
     
Public Enum EShellShowConstants
    essSW_HIDE = 0
    essSW_MAXIMIZE = 3
    essSW_MINIMIZE = 6
    essSW_SHOWMAXIMIZED = 3
    essSW_SHOWMINIMIZED = 2
    essSW_SHOWNORMAL = 1
    essSW_SHOWNOACTIVATE = 4
    essSW_SHOWNA = 8
    essSW_SHOWMINNOACTIVE = 7
    essSW_SHOWDEFAULT = 10
    essSW_RESTORE = 9
    essSW_SHOW = 5
End Enum