They may still be a little unstable with regards to threading on Mono (which sometimes cuts a request short and strange things like that), but the code works at a prototype level.
Not sure it will help with your issues but you may have to send additional headers to solve a problem specific to I.E. (I.E. caches XMLHttpRequest responses).
From my souvenirs, the problem was with the '/auth' call.
'Last-Modified' = ''
'Cache-Control' = 'no-store, no-cache, must-revalidate, post-check=0, pre-check=0'
'Pragma' = 'no-cache'