To begin with set the hlookat and vlookat of the view tag to 0. For every spot tag which are children of the google maps plugin, set the heading to -90 so that every spot will be pointing to North (top of the screen) by default. Let the user view the tour and rotate the panorama and keep a tab on the radar on the google maps. Based on when the hotspot is visible on the tour and when the spot is coming into focus of the radar, change the value of the heading.
If the radar should be oriented towards East (right of the screen), it's value should be 0, for West (left of the screen) it should be 180/-180, for South(bottom of the screen) it should be 90, for North(top of the screen) it should be -90 as mentioned earlier.