Bought XPS 8940 and found that there is only one 2.5" HDD caddy. I am installing two HDDs. Where and how can I get one more? I called Tech Support who said I can buy from Dell Sales, and gave me a phone number. I then called Sales, she told me Dell does not sell it. I searched and searched on the web but not in success. There are similar parts, which I bought some. But dimensions are wrong because they were for other Dell PCs.