This is a very good question that you have and I would like to be of some assistance to help you understand what is going on. If the Slingbox is getting an error that HDCP is a problem than there is not a way to get around this other than removing the HDMI cable from the cable box. This is a setting on the cable box and something we can not control. I will post a few links below that will help you understand what HDCP and SOC are.
When I connect my set-top box to my TV with HDMI connections, I can't stream video at all using any version of SlingPlayer. Why?
Hope this helps,
Sling Moderation Team