The problem is that this is borderline "offensive behavior" on the Internet. You might have a good reason for doing this, but there are two problems. First, I'm SO annoyed with spammers as a class that I'm not willing to chance helping one, so unless I knew you well enough to be certain that you would behave yourself I'm not willing to hand you a "loaded weapon" for spamming. More importantly, even if I was comfortable helping you to work around this problem I would never post that help in a public place where any spammer could access it.

There are work-arounds for this problem. The work-arounds usually aren't simple, and your present approach will only mitigate the problem a very small amount and will hit a larger problem very soon.

This is the internet, you're free to do what you please until you hit a limit (like the telstra limit you've already hit). You really need someone that understands more about the underlying technology and the internet culture to help you work through this. Just trying a "brute force" fix for the problem won't get you very far and I'll bet that it will leave you in a bad place.

-PatP