Restock Button - not there

We are trying to set up our return authorization process and are having problems getting the "restock" check box to appear. We do the return authorization, then when we go in to receive the return, there is a column on the line item that says "Restock?" but there is not anything under it to check or anything. We have unchecked the "Restock Returned Items" under the accounting preferences.

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We figured out that when we do an RA for a "kit" item, the restock button does not appear but if we do an RA for an individual inventory item the restock button does appear.  Is there anyway to have the system accept a "Kit" item back into inventory?? Our sales orders work that way, it would seem that a return should work the same??? NO??