Alpine 8048 - need help

I've successfully installed the 8048 in a 95 Camry...but the radar sensor doesn't seem to be working very well.  I've mounted it in the center console cubby hole.  It works but I read in the owner manual "CAUTION: DO NOT PRESS THE TX AND EXT BUTTONS SIMULTANEOUSLY WHEN THE SYSTEM IS IN THE VALET MODE. PRESSING BOTH BUTTONS WHEN THE SYSTEM IS IN VALET WILL CAUSE THE SYSTEM TO ENTER THE RADAR SENSOR SENSITIVITY ADJUSTMENT MODE. IF THE SYSTEM ENTERS THIS MODE, PRESS AND RELEASE THE TX AND EXT BUTTONS SIMULTANEOUSLY TO EXIT THIS MODE AND RETURN TO A DISARM STATE."  My question is how do you adjust the sensor?  I pressed the TX button and hear one beep and press the EXT button and hear two beeps.  Anyone know how this feature works?

If i remember correctly on the 8028 when entering the sensor adjusting mode there are 2 stages. The first is the pre warn and the second is the final trigger. Pressing the TX will increase the sensitivity and the EXT will decrease it. When either max or min has been reached the siren will chirp twice...although the 8048 could be different