The documentation for the LiveCycle SA's don't specify anything other than creating the SA_DS data source when using WebSphere for WebLogic. This data source name has already been added to the common building block and will automatically 'pickup' when LiveCycle is restarted. Here's the error message that you'll see if it hasn't been created.
[9/23/10 15:27:02:565 EDT] 000000aa RegisteredRes E WTRN0062E: An illegal attempt to use multiple resources that have only one-phase capability has occurred within a global transaction.
[9/23/10 15:27:02:573 EDT] 000000aa LocalTransact E J2CA0030E: Method enlist caught com.ibm.ws.Transaction.IllegalResourceIn2PCTransactionException: Illegal attempt to enlist multiple 1PC XAResources at com.ibm.ws.Transaction.JTA.RegisteredResources.enlistResource(RegisteredResources.java:416)