asynchronous pluggable protocol info

Does anyone have any suggestions on where to find any good
documentation on how to implement asynchronous pluggable protocols?
I've found plenty of descriptions of the basic stuff, but not much
detail.

For example, the APP that I implemented a while back worked fine until
I started using XMLHTTP for some requests. In that case the URL that
my IInternetProtocolRoot::Start implementation gets is garbled.
Instead of "myproto://path/to/page.html" it is getting
"myproto://path/to/page.html/path/to/page.html". I suspect that it is
my implementation of IInternetProtocolInfo::ParseUrl (I only handle
PARSE_SECURITY_URL), but the documentation is pretty sparse on ParseUrl
and most of the examples that I've seen either don't implement it or
just return INET_E_DEFAULT_ACTION.

Any ideas?

Thanks

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