Hi
What is your IIS default page name on you IIS server ? Is it 'index.html' ?
Cant you just tell your IIS server that if someone asks for "/", then serve up "default.aspx"
If that does not work/help and you want to use iRules, then you could certainly have a rule that says "if client asks for / , then serve /default.aspx"
Did you use HTTPWatch or HTTPFox to verify the client browser does not get the redirect to /default.aspx ?
I was wondering how you knew it was coming from the server, but not making it to the client ?