My sister's van has a Pioneer DEH-P4800MP radio which had XM satellite programmed. They lost the XM signal and while on the phone with XM were told they had to push the "Reset" button so XM could resend the signal. They can't find any "Reset" button. How do they do this so XM Radio can "reinstall" their XM signal for a paid-in-full Subscription? Thanks! Saf