Unfortunately, it's not that simple.
IOS has no provision for running drivers, like a computer running Windows or OSX. Devices have to either meet the MFI (made for iPad) standard, or meet the CCK's limited implementation of USB. Remember that Apple only expected the Camera Connection Kit to be used to connect with digicams (thus the name, obviously)...
Meanwhile, over in the computer audio world, manufacturers have been using fancy proprietary drivers to squeeze out marketing advantages. Because the basic USB implementation (known as USB Class Compliant) is so restrictive, in many cases the manufacturer doesn't even bother to offer a dumbed-down USB CC mode.
This, the relatively small number of class-compliant interfaces that will work with the CCK, mostly entry-level ones at that. The last time I looked at the Auria compatibility chart, RME had about the only box that broke the $1,000 mark.
Going back to the Lexicon, you'll need to check their website. If it's Class Compliant, that information will most likely be buried either on a specs page, or in a downloadable user manual.