It would appear that APXS is included in the apache-devel rpm's - have you installed these for the version of apache that you are running?
I haven't been able to find an rpm for ajp13 though, so it looks like you may have to build this yourself. If you manage to build it successfully, it may be an idea to build an rpm for it as well if you know how to - I may be asking too much of you though.
Just thought it would be nice to put something back into the community.