recording audio and guitar through podxt live

hi everyone my name is gavin and im new here.i was wondering if anyone could help.im running my guitar through SOFTWARE LINE 6 GEARBOX and i get a great sound.my guitar is plugged into line 6 ux1 hardware via usb.i also have a creative elite pro soundcard in my computer and with the soundcard come software to record WHAT YOU HEAR through the line 6 ux1.so i play a backing track through media player and i play along with my guitar and start the recording but im only getting the guitar recording and not both the backing track and guitar.can anyone help please.do i need some different software to accomplish this.thanks gavin.