Need some help using Authorize.net's ARB API...please.

[crownmultimedia]

I am using a subscription management software called Omni-Secure (OSS) and I have my Authorize.net merchant account linked to this software. For some reason, OSS has disabled the "unsubscribe" link in their latest upgrade and my users can't manually cancel their own subscriptions. I have to manually cancel each one myself and it is just too time-consuming to do so.

I read the Authorize.net ARD developer's guide and downloaded the sample code that allows me to set up an UnSubscribe API call from my website using PHP, but I am a little confused as to how I should setup this custom UnSubscribe link.

Can anyone offer some help and advice? Thanks.