A) Newest Beta of XWE has lowercase naming.
B) Use the "clean up" function in XWE and crack open a hex editor. Scroll down (all the way, yes all) and change the A's and B's to lowercase. Since Hex editors overwrite the next character, highlight the upper-case letter and enter the lower-case version. You only need to do this on the "A" and "B" lumps.
(And yes, all this is coming from a level designer. Don't ask.)
If anyone could add on to my hex thing, much appreciated. I just know I missed something.