<blockquote> I've had nothing to do with oacs 4.5 so far
</blockquote>
try it and you will never want to go back ...
<blockquote> would it be complicated to use it on a 3.2.5 system?
</blockquote>
You could try it by unzipping the .apm file, copy the tcl/tclwebtest-procs.tcl someplace where it is sourced and backport the page www/admin/test-run.tcl where the stuff actually happens, but I wonder if that would be worth the effort.