I finally got wwassignment4 working with apache2, but one thing I learned along the way is this - with at least some soap configurations, there are various errors that can crop up when you try the "go to webwork2_rpc" test. In my configuration, and apparently others as well, this generates an error. However, this does not mean that iy doesn't work, as I found out.
One of the frustrating things is that some versions of soap fail to define a constant that essentially means "page not found". This is relatively easy to fix (after a day of work), but it doesn't help, since the real problem is that the webwork2_rpc isn't being dispatched properly. However, moodle nevertheless connects, if other things are set up properly .
I'd suggest that the installation instructions be changed to either remove this test, or at least point out that if it fails, one should check to see whether moodle connects anyway.
Incidentally, one of the suggestions in the forum was to revert to an older soap implementation. I did this, with no effect whatsoever, so I've gone back to the current soap.