You have to do some extra work. The guy in the meeting-room of the highwind has a useful script with PHS. But using tents, well i show you my mog script:
0 Deactivate the movability of the playable character
2 Disables access to the main menu
4 Play animation #1 of the field model and reset to previous state (speed=1)
7 Var[5][11] = 0 (8-bit)
11 Resizes/Repositions the window #0 (X=8, Y=8, width=138, height=73)
21 Ask Question "“Schlafe{, }schlafe …” Ausruhen Speichern Vergiss es" in the window #0 (and put selected answer in Var[5][11]) first line=1, last line=3
28 If Var[5][11] == 1 (else jump to byte 99)
34 Var[15][20] = amount of item Zelt in the inventory
39 If Var[15][20] == 0 (else jump to byte 60)
45 Create window #0 (X=65, Y=10, Width=173, Height=25)
55 Displays the dialog "Du brauchst ein Zelt zum Ausruhen." in the window #0
58 Jump to byte 121
60 Fades the screen to the colour RGB(0, 0, 0) (speed=8, type=2, adjust=0)
69 Wait for fade
70 Restores full HP and MP of every available character and removing status effects
71 Wait 200 frame
74 Fades the screen to the colour RGB(0, 0, 0) (speed=12, type=1, adjust=255)
83 Wait for fade
84 Remove 1 item(s) Zelt from the inventory
89 Resizes/Repositions the window #0 (X=65, Y=10, width=173, height=25)
99 If Var[5][11] == 2 (else jump to byte 115)
105 Wait 4 frame
108 Show menu Save (parameter 0)
112 Wait 1 frame
115 If Var[5][11] == 3 (else jump to byte 121)
121 Activate the movability of the playable character
123 Enables access to the main menu
125 Return