It's possible to add custom brand name for your stock item in Loaded.
Here are couple simple steps to do it.
First, you need to create a purchase order.
Go to Stock>Ordering, there press green 'New' button and then 'New purchase order'.
In following window click 'Add item' and choose the item from the list that you would like to add a new brand name for.
Then click on default brand's name (would be listed as 'Not Set' below 'Brand' column), click 'More' in the list you'll see after.
Then just press 'Add Custom brand'.
In the window that opens after it types the brand's name and saves it.
If there is a need, you could do it several times for each item that needs a new brand's name.
After everything is done you could close the purchase order without saving it, don't worry changes you've made would be saved in the system.