.NET Connector & PAM problem

[B P]

Hi
Apologies if this is really in the wrong forum - any mods please move or delete as appropriate.

I have a bit of client-talking-to server problem I hope somebody can point me in the right direction with. I think this might be a MySQL connector Net problem - but I'll be happy to be corrected.

Ok - setup
MySQL server : CentOS 6.2 x86_64. Running MySQL 5.22 Enterprise

Client : Windows Vista x64, client is using MySQL-Connector-Net-6.5.4

I'm currently trying to evaluate the different versions of MySQL. I'm trying out the enterprise version (partly because of the OS account authentication plugins), but I've come up against a problem. I want to use the authentication_pam.so plugin, so that I can tie user authentication in with the user accounts on the Linux system already. I have the plugin working OK (that is, I can use the unix account username & password, which authenticate via pam) if I connect using mysql -u <username> -p at the server command prompt, and also if I use mysql -h <serverIP> -u <username> -p mysql on the client machine. Also MySQL Workbench on the client machine works fine as well.

The problem comes when I try to connect to the server from the client machine using the MySQL-Connector-Net-6.5.4 (btw, I'm using this in C#). If I connect using an account that doesnt authenticate via pam (e.g. the mysql root user), the connector works absolutely fine. However if I use an account that authenticates through pam, then I get the message

"Client does not support authentication protocol requested by server; consider upgrading MySQL client"

and the connection fails.

I'm using a connection string "SERVER=serverIP;DATABASE=mysql;UID=unixaccount;PASSWORD=unixpassword;"

any thoughts gratefully accepted.