I'm afraid you've hit a limitation in DotNetOpenAuth due to its use of
Dictionary instead of NameValueCollection. You can only have one parameter
per name. Now, I *believe* if you just have one type parameter with a
comma-delimited list as its value that some services will interpret that as
equivalent to multiple type parameters. You can try it against LinkedIn to
see whether that works.
"I [may] not agree with what you have to say, but I'll defend to the death
your right to say it." - S. G. Tallentyre