[Exim] Exim smtpauth + Courier authdaemon

I've run into a snag in implementing smtpauth using courier's authdaemon. After checking through the mailing list archives and the docs, I am unable to find a solution to my problem.

I keep getting "Incorrect authentication data" despite using known good username & password values.

Is there some way I can check to make sure that exim is properly accessing courier's authdaemon socket, or to see what values are passed between exim and the authdaemon?

I'm running Exim 4.3 and Courier 0.44.2 on an installation of RedHat 7.2, which I updated from Exim 4.22 and Courier 0.43.1 in the hopes that the ugrade would have fixed my problem.

The authenticators I'm using are as follows:

plain:
         driver = plaintext
         public_name = PLAIN
         server_prompts = :
         server_condition = ${if eq{${readsocket{COURIERSOCKET}{AUTH${eval:13${
sg{$2$3}{.}{+1}}}\nexim\nlogin\n$2\n$3\n}{5s}{ }{FAIL}}{FAIL }{no}{yes}}
         server_set_id = $2

login:
         driver = plaintext
         public_name = LOGIN
         server_prompts = Username:: : Password::
         server_condition = ${if eq{${readsocket{COURIERSOCKET}{AUTH${eval:13${
sg{$1$2}{.}{+1}}}\nexim\nlogin\n$1\n$2\n}{5s}{ }{FAIL}}{FAIL }{no}{yes}}
         server_set_id = $1

---Brett.