It all depends on where you do want it to appear in the list. As you note, the reference list is generated by Endnote and thus, it can’t be manually adjusted until lyou are ready to submit the manuscript, when you can make a copy and unlink the endnote fields and mess around with it til your heart’s content. But you can also adjust endnote to include or adapt a reference type to produce what you want, automatically. How do you want it to appear, and which field do you want to alphabetize it as? If you just want it at the end, that can be adjusted to with some tricks of the trade.
Also providing your Endnote version (X5?) and word processing program/version will help one of us to use examples from that version, as there are suble differences between the menu locations.
(added in edit-- you want it first? then give the order of fields that you want to appear).