Holas, no conozco mucho sobre DataExpress y el uso de transacciones, pero segun lei el api de DataExpress, lo que tienes que hacer es al crear un DataStore tienes que asignarle un TxManager, que llegaria ha ser tu administrador de transacciones, esa instacia de TxManager que crees tiene la opcion de activar o desactivar el uso de transacciones y algunas otras cosas mas que puedes ver en la descripcion de los metodos, y con ayuda del DataStoreConnection defines que tipos de permisos va a tener la conexion si va a ser solo lectura, escritura, commit, rollback, pero eso depende de que tu DataStore tenga un TxManager, aqui te dejo un fragmento de lo que lei en el api de dataExpress:
Cita: Creating the DataStore file
There are two ways to create a DataStore file, depending on how you are using the DataStore with a StorageDataSet - either as persistent off-line storage or as an embedded database through the DataExpress API. Either way, the name of the DataStore file is controlled by the DataStore object's fileName property, and starts out with the same general steps:
1. Instantiate the DataStore.
2. Set the fileName for the DataStore file.
3. Set any other properties that must be set at create-time, like the blockSize, if desired.
4. To make the DataStore transactional:
1. Instantiate a TxManager
2. Set its properties if desired
3. Assign it to the DataStore's txManager property
4. Assign a name to the DataStore's userName property
When using the DataStore with a StorageDataSet, you continue with these two steps:
1. Assign the DataStore to the StorageDataSet's store property.
2. Assign a name to the StorageDataSet's storeName property. This name will identify the StorageDataSet's data inside the DataStore.
This will create the DataStore when necessary. The alternative is to create the DataStore manually, which is more likely when using the JDBC driver to access the DataStore. There is only one additional step:
1. Call the DataStore's create method.
Because the DataStore is a subclass of DataStoreConnection, the create method (if successful) results in an open connection to the newly-created DataStore through the DataStore object. You can then use methods in the datastore package (the DataStore API) and a local JDBC driver simultaneously to access the contents of the DataStore.
ahh tambien te dejo la direccion de la pagina del api:
API DataExpress
cya