Auto login for RDP on win 2008 r2 not working

I'm somewhat new to devolutions RDM, but have been using the product heavily for the last few days.

One thing i've noticed - i can't auto log into my 2008 r2 terminal servers when the sessions are embedded (tabbed).

I am greeted with this message: The user name or password is incorrect.
Screenshot of example attached.

If i use the exact same creds and make the session "external" - i can auto log in. It seems like embedding the session in RDM creates the issue.
While i have somewhat of a workaround, this is not as flexible as embedding the session would be - I'd much rather embed all sessions.
I don't notice this issue with win 2003 or win 2008 - just win 2008 r2.

i'm using RDM enterprise edition v 8.2.0.0 with remote desktop version 6.1.7601.17514.

any info would be great.