Changing Gateway temporarilly

[Jos Chrispijn]

Running FreeBSD v9 using Gateway1 (50/10Mbit) with Postfix and Apache2
Don't have two NICs in my server.
Running IPFW.

I have another Gateway2 (200/35Mbit) which I would like FreeBSD to use 
for certain internet traffic (download ports and some uploads).
Can you tell me how I could realize this? 2nd Nic is no option.

Thanks for your reply,
Jos Chrispijn

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