In case anyone's interested, I was able to solve this and can now successfully relay through my gmail account, more specifically I relay through my own domain which is hosted through google's "free apps for your domain service"...
The way I solved this is I point the forum's SMTP settings to 127.0.0.1, where I installed a free app called stunnel. stunnel will take the communication and encrypt it over SMTPS (SSL) to google so it can be securely relayed!! ISP's (cable modems etc) are really starting to crack down on outbound SMTP, so this is an awesome work-around!