If you want to use an XADataSource, the JBoss JCA can use the standard API.
If it is a non-XADataSource that does internal pooling (such as Oracle's DataSource for use with RAC), then the pool will not understand the transacting or security configurations (nor any other component that expects the connection to be controlled by the JCA).
These DataSources are intended for use outside a J2EE environment.
JBoss uses standard JDBC drivers and adds the behaviour to turn them into DataSources with the full J2EE contract.
Non-XADataSource datasources should only be used by administrators with a thorough understanding of the topic and its inherent problems.