Vizio L37 HDTV and SA Explorer 3100 HD

Greetings:


I recently purchased a Visio L37HDTV. I had COMCAST install a Scientific Atlanta, Explorer 3100 HD. The COMCAST remote allows me to change from one station to another; I need to press the input button on the Vizio remote to change from Analog HD1 and/or TV (to view channels below 100 to prevent burn-in), but I can't use the COMCAST remote to access other features( for example volume, PIP, CC). From what I can see, the TV cable is coming out of the wall, into the SA box, then a cable is coming from the box into the TV (I have to check if the connection is going into the Digital Antenna Cable or TV Cable Antenna). Is this connected correctly? Do I need any other cabling setup, such as a splitter to allow me to connect both to the Digital Antenna Cable and the TV cable antenna?


The on-tech who installed the cable box, said that I would need to get a software upgrade by calling COMCAST, but after speaking to COMCAST support, I learned that this was not correct, and so, I am starting to question the tech expertise. The TV has PIP capability, but I can't get it to work. And with football season in full gear and hockey starting up soon, I need help!! If you need other info, please let me know. Your ideas and help are appreciated