Sharp Aquos Crystal X (402SH) hard reset how ?

I have a problem with my "sharp softbank aquos 402SH
I setup a pattern lock. Since I have not used the phone for some time I cannot remember the pattern anymore.
I thought an unlock with a hard reset is no problem. But I found no way to boot into recovery mode(tried power and minus button, power and plus button to boot).
Also the device did not show up in adb as a device(Windows 8/Sharp USB driver installed) but was recognized as a storage device.
The user manual says:
"Do not forget pattern, Lock No. passcode or password set for canceling Screen lock(write it down if necessary). If you forget it, visit the nearest SoftBank Shop for recovery procedure."
As I live in Sudan and there are only softbank stores in Japan. So this is not possible for me.
Is there any other way to hard reset the device?