If you mean the laptop's headphone jack (not the HD500's), the answer is yes, it can be made.

You need to, either configure Win7 to use the integrated soundcard as default, or configure the specific program you're using to play the backing tracks to do just the same, that is, using the integrated soundcard as output device.
This way, the presence of a connection between the Pod and the computer won't make any difference in the output path. The computer will keep using the Pod's USB to exchange data.ce

Hitchface: there are ways to get many soundcards to run in tandem, not just two, though windows will only use the one you have selected as default to output the audio of those programs that don't admit custom audio output settings, like windows media player.
Example 1: I have a MOTU 828mkII plugged to this computer. Each of the stereo pairs of outputs it provides can be selected as windows' default sound output, or I can choose the integrated soundcard... or hdmi, or any other audio device I happen to have in (or plugged to) the computer.

Example 2: Somebody at home wants to use the computer to play music while I'm using it to watch a movie. I can do that using two different media player programs. One of them (at least) must admit custom audio output settings (i.e.: Winamp)  and the other may use windows' default audio device. I configure Winamp to use the computer's integrated soundcard as default, so that anything Winamp plays will be output through the mini jack connectors on the back (and/or front) of your computer. Then I configure Win7 to use the Pod's stereo out as default audio device, so that Windows Media Player will use the Pod. Both players can be producing an audio output simultaneously through different devices.

If you have further questions or doubts feel free to ask.