There are four transaction management properties available, please refer the guide
http://download.oracle.com/docs/cd/E15523_01/web.1111/b31974/taskflows_complex.htm#BABICCGC for detail description.

In short :
1) - does not participate in any transaction management
2) Always Use Existing Transaction - the bounded task flow participates in an existing transaction
3) Use Existing Transaction If Possible - bounded task flow either participates in an existing transaction or starts a new transaction
4) Always Begin New Transaction - new transaction starts when the bounded task flow is entered

2) Always Begin New Transaction : There is already a example exists by andre use existing transaction example