Motion Detection Enable    Disable  
Time  Always 
 Schedule 
 Day Mon  Tue  Wed  Thu  Fri  Sat  Sun  
 Time Period   
Start :  7:00
Stop :  10:00
(This will change tonight to about 21 hours a day.) 
 
Sensitivity  85 %  (0~100%, high sensitivity makes the motions easier to be detected.)  
Detection Areas  Use mouse to click the blocks where you want to monitor for motion.
I clicked on all menu items (left column) under the Tab "Setup". I don't see anything titled Day/Night settings.