Informix driver for VAJ EJB Server

[Graeme Brown]

Can anyone tell me the correct setting for the "connection type" property for an EJB Server in VAJ V4.0 to access an informix database?
I have informix jdbc installed and running and can access the database using "com.informix.jdbc.IfxDriver". But when I try to set up a datasource in the Websphere Test Environment, or to configure the properties for the EJB server, I am not being given an informix option in the drop down lists.
I guess there is some other driver class I need to use, but what is it?
Thanks
Graeme