Xfinity XR15 remote won't control Pioneer Receiver VSX-819H

I just set up my xfinity x1 new box.  The Xfinity XR15  remote will change channels and operate the DVR.  It turns off the TV but not the receiver.  It also does not operate the volume.  Basically, it doesn't control the receiver at all.  I have a Pioneer Receiver VSX-819h which is from 2008.  When I called Xfinity to troubleshoot this, they walked me through reprogramming the remote.  The remote thought I had a Pioneer TV but my TV is a Samsung TV (which is also from 2008).  So I changed it to Samsung TV.  The remote will control the TV volume but I use the volume through the receiver.  So we went forward with the receiver setup.  I tried 8 different codes for Pioneer and none of them worked.  Xfinity told me to call Pioneer to get another code.  I just got off the phone with Pioneer and they didn't have any codes.  They suggested I do something with the Pioneer remote and the Xfinity remote to have the Xfinity remote "learn" the Pioneer remote.  Not sure how to do that.  So as of now, I have to use 2 different remotes.  I use my old universal remote to turn the tv, operate the volume,  and change the TV input.  I use the Xfinity XR15 remote to change the channels and use the DVR.  Does anyone have any knowledge about this and have any suggestions to get my Xfinity XR15 remote to control my Pioneer receiver so I don't have to use 2 remotes?