Adding a custom field that is not filled my the feed but by a text inputted like the merchant name

Hi David,

I coded a script that automatically creates a category hierarchy from the feed data.

For that I added a couple of custom fields in that I explode the subcategories of the category field on import time and go through thease fields in my script.

To simplyfy the process I would like to enter the character that has to be used to explode the subcategories when I register the feed. I wouldn't have to use the seperate customfields I created for the subcategories and could explode the categoy path directly in my script.

How would I create a custom field that has no dropdown but a simple input box like it is used on the merchant name?

Thank you and I hope you enjoyed the bank holiday

Sven