Man, unless you want to buy one of these, it is tough to find support. I did find the universal code name for an 18 digit code - ean-18.
I see that that scanner has capabilites of: Code11, Code39, Code93, Code32, Code128, Coda Bar, UPC-A, UPC-E,EAN-8, EAN-13, JAN.EAN/UPC Add-on2/5 MSI/Plessey, Telepen and China Postal CodeInterleaved 2 of 5, Industrial 2 of 5, Matrix 2 of 5.
Of course the ean-18 is not one of them. All things are possible if you know the requirements, and now you know that you have a requirement of ean-18 reading!