Todd,
I don’t think this is currently possible, although I haven’t dug into the underlying services to see what could be tweaked. However, on a previous project we had an auditing requirement that we met by allowing the connection to be established using the pre-configured account and then running an Stored Procedure to set the audit data based on the actual user account requesting the connection. This may not work for you if authentication is your primary goal, but it at least allows for an audit trail. HTH.
#webMethods#Integration-Server-and-ESB#Flow-and-Java-services