The ELIS system requires that you manipulate your IV Case Number and Registration Number in an odd way. You must add an 'A' in front of your Registration Number and then pad out the remaining numbers with enough leading zeros to make a total of nine digits (the 'A' is not counted, of course). You must also leave off the last two numbers of your IV Case Number. For example, see below:
IV Case Number on Visa: WTF201491100201
Registration Number on Visa: 86753091
IV Case Number for ELIS: WTF2014911002
Registration Number for ELIS: A086753091
What a wonderful system. It was surely created by the greatest minds of our time.