Instead of webmail forwarding your email to Gmail, consider configuring Gmail to fetch your email with pop3. This way it's a bit more appropriate when it comes to email headers. -- [Sig removed by Administrator: signature can not exceed 20GB]
I do that now and it works well. It isn't as fast though, forwarding will be almost instant.. Gmail only checks for messages every 15-20 minutes. You can force it to check, but I don't think there is an option to change how often it checks.
In your day to day life, does 15-20min delay really matters? And if you are explicitly expecting an email, then simply manually refresh it. -- [Sig removed by Administrator: signature can not exceed 20GB]