[Solved]Costum Fields

In the hikashop options of your products listing menu/module you will find an option on the right area in order to display custom item fields if you're using the latest version of HikaShop.

Are you sure that you're editing the correct product listing options ?

Then, you must have modified one of the view files of the product view before updating HikaShop. Do a backup of your modifications in the files of that view, delete them via the menu Display->Views and try again.

If it's a custom field of the table "item", it will work with that option unless you've edited that view before updating hikashop.
If it's a custom field of the table "product", you will have to edit that view file in order to display the custom field yourself. It's quite easy:
echo $this->row->CUSTOM_FIELD;

where CUSTOM_FIELD is the column name of your custom product field.

The custom fields of the table "item" are set by users for products in their cart. So the data is of course not attached to the product but to the link between the cart and the product, which then becomes the product in the order.
So there is no meaning in importing a value into such custom field since it's the customers who enter data for it, not you.

I didn't understand your second problem. Could you explain more what you want to do ? Maybe with a screenshot ?

Could you do a screenshot of your custom field so that we can see what you did ?

So you need to add the code:

echo $this->row->produktnummer;

Make sure that you enter something for it in the product. You can use the column produktnummer in your CSV in order to add data to it.

See the column for the product name:
<th class="hikashop_product_name title" align="center">
<?php echo JText::_( 'PRODUCT' );?>
</th>

Just do the same after it:
<th class="hikashop_product_name title" align="center">
<?php echo JText::_( 'My column' );?>
</th>

Then, in the same manner, you see the display of the product name from:
<td class="hikashop_product_name_row">
<span class="hikashop_product_name">

to:
</span>
</td>

Just add the same code after it with the line of code I gave you in my previous post.
It's more about HTML than coding...