My little LazyWeb mewl from a few weeks ago didn’t really generate much in the way of attention, though one poster, Matan Ninio, was apparently able to get things working with a manually specified proxy:
The problem seem to be that iCal does not know how to work with a proxy.pac file, but does know how to work via a proxy. Just enter the proxy address and port directly, and suddenly all is well again. (at least thats the case with our 10.5.2 machines)
Life is like a diaper — short and loaded.