As i looked at the case's front panel which i took off during the installation, i got an idea to use it. I drilled a hole on the front panel and put the main power rocker switch (from battery).
Reset (momentary) switch is also at the front panel.
At the back of the golvebox CD changer hole, there are 3 screw holes (i don't know what these holes are for, but i guess they are to fix cover plate for car model without CD changer). So, i made fix legs for the front panel using these holes. I used epoxy putty to form those legs.
Lastly, the case's front panel is installed to the glovebox. Now with power and reset switches, also power, harddisk, and PSU LEDs are wired to display at the front panel.