Help pairing remote to soundbar

I recently bought a Sceptre tv. Love the tv, hate the speakers. I purchased a Sceptre sound bar. It sounds great, but I can’t pair it to the Comcast remote, xr11. Sceptre does not show up as a model to choose from. I called Comcast, they said call Sceptre. Sceptre said to call Comcast. My husband refuses to have to use two remotes. Any suggestions are greatly appreciated.