In soapUI 5.2.2 I have to use a property or modify the xml file directly to be able to test against a URL with mixed case it should just be allowed. Refer to Question on How for the the workarou...
rupert_anderson, My understanding was that one needs to be in agreement with SmartBear to become a contributor. May be the same is case with Issue, don't know.
Here is the documentation to take part in contribution:
https://www.soapui.org/developers-corner/contribute-to-soapui.html