I just recently installed Windows and downloaded IE8 again and it seems that pmxdr works fine with the exception of one small MessageEvent.source bug in the host library that I fixed in version 0.0.5.
I went to check out if the XDomainRequest examples I created worked, and to my astonisment, they ALL failed except for the simplest example. It turns out, contrary to what I assumed of it only not supporting responseXML, XDomainRequest also doesn’t support much of the basic HTTP header functionality offered in XMLHttpRequest, such as setRequestHeader, getResponseHeader, and getAllResponseHeaders. This means that my implementation of XDomainRequest actually offered more functionality than IE8’s implementation.
Due to this, I have changed the XXDomainRequest library to implement a generic XDR constructor and I have renamed the library from XXDomainRequest to libxdr. The examples have been changed to use new XDR() instead of new XDomainRequest() so now every example works in IE8.