Question on XM Radio Delphi Antenna Placement

Good Guys salesperson says the XM Radio antenna must be next to a window so the Delphi Home unit(with docking station) can receive an XM signal. At the Home Entertainment Show in San Francisco, I was told the antenna could be placed on top of my TV (approx 12 feet away from a window). Before I purchase, I need to know the antenna requirements to receive the XM signal. If the home unit needs to be next to a window, I have to run wire under the floor. If anyone owns the XM Radio Delphi Home unit, please advise where you have the antenna and what works? Can I place the antenna under a skylight window? Thanks..
I received the answer below from XM Radio:

In most home applications in the US, the XM radio antenna will require placement in a window with a clear view of the Southern sky. The antenna features a weather-resitant design and can be mounted otdoors if that is the only way to obtain a clear Southern exposure.

Delphi is releasing a 50' antenna extension with improved design in an effort to mitigate any field issues that may arise from using the now out of stock design.

Approximate date of availability is the week of July 14th. And of course, we apologize for any inconvenience, but felt it important to release the new product without retired inventory remaining in the field. The new design should also address concerns about use in the boom box as well.