Man, you're not getting a connection from the pool using the above statements, not even in WL.
To use the connection pool you need to configure a datasource and bind it to a JNDI name. There is plenty of example in the jboss distributions: look for the "sample/jca" directory for this.
Later you need to lookup the connection using JNDI. If you don't know how to do that, I recommend finding and reading a good book on it. "Mastering EJB" talks about this, albeit superficially.
In weblogic the statements will get connection.
and jboss support JTS1.0 spec,I think it also can get datasource or non-jts-datasource from its driver.