What version of IIS are you using?

Are you using an Integrated Application pool?

system.webServer section only applies to integrated app pools.

I would use something other than Default.aspx

Seems like you could do it directly in the root web.config file but use the location path /WebStore/OrderDetail.aspx

You could also install the IIS Url Rewriter Module and use that to do the redirect.

Hope that helps,

Joe

Assuming the mojoPortal site is configured to use the mojoportal integrated app pool that should be fine.

Did you try putting it in the root Web.config as I mentioned and remove the extra web.config from the WebStore folder so it does not interfere. If you still get access denied it means the redirect is not working for some reason.

Again you could also accomplish this by installing the IIS Url Rewrite module from  platform installer and configure it to do the redirect also using web.config settings. If you google that module you can find tutorials how to do it.

Hope that helps,

Joe