The direct message API wasn't dropped from the Yedda.Twitter library. I didn't exist when we originally wrote it.

You can get the most up-to-date code of the Yedda Twitter API wrapper here.

I would, however, recommend that you stop using this Twitter API (the one that takes a username and password) and start using the OAuth based API. It is much more secure for your end users as well as provides the right way of using an API on behalf of a user.

I would suggest that you move to use TweetSharp which is a C# library that uses the OAuth API of Twitter.