Limit SC set up and add item N/A - do not use

We are on SRM 7.01 SP 10

We are trying do enter a limit SC via professional shop.    An entry labeled N/A - do not use on the Add Item pull down seems to be linked to the item SC process because the pop-up box has value limit, between dates and so on.   Two questions:

1)  How do we change the N/A - do not use  label?

2)  All of the entries on the pop-up box are greyed out - how can we make those fields available for editing?

Regards,

Sandra