Hi,
Change the line:
return '<input id="'.$this->prefix.@$field->field_namekey.$this->suffix.'"'.$size.$js.' '.$options.' type="'.$this->type.'" name="'.$map.'" value="'.htmlentities($value, ENT_COMPAT, 'UTF-8').'" />';
to:
return '<input id="'.$this->prefix.@$field->field_namekey.$this->suffix.'"'.$size.$js.' '.$options.' type="'.$this->type.'" name="'.$map.'" value="'.$value.'" />';
in the file administrator/components/com_hikashop/classes/field.php in order to fix the behavior. We'll add that patch on our end with the next version.
Also, you might have to turn off the "input filtering" setting of the custom field.