PVR-150 Unable to change channels on Digital receiver

[Swiftfeet_8]

I recently bought the Haupagge PVR-150 and it came bundled with an IR-Blaster. I am able to change the channels using Hauppages included PVR software, but when I try to change channels in MediaPortal I get nothing but static. I've searched through the Wiki and the documentation and have found nothing. If I disconnect the digital converter box, and just tune to the regular Analog channels I can flip through them with no problems. However, the image quality on the channels is really poor. I checked my connections to make sure they were tight. I have 2 splitters in between my HTPC and where the cable comes in from the outside. Hopefully it is something simple that I have overlooked.

My digital receiver is a Magnavox from Charter.

In short, I am able to control my STB. However, I can't control it through MediaPortal.

Thanks.