Hello,
1 - You can use any image you want ; it'll just change your settings because you will display the elements at other positions.
2 - The date display is using HikaShop/Joomla function to perform that display.
The input box below the dropdown is there for additional parameters, such as the date format in your case.
Just enter "%d-%m-%Y" and you will have the display you want.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.