Different systems, same matrix representation, similar properties

In recent paper [W. Cheng, Phys. Lett. A 364: 517-521 (2007)] we take the original 4 times 4 bound entangled states in [S.-M. Fei, et al, Phys. Lett. A 352: 321-325 (2006)] as 2 times 8 states and show that it is still bound entangled. Whether other bound entangled states, especially 4 times 4 bound entangled states, have the same property or not? In this paper, we consider another 4 times 4 bound entangled state in [F. Benatti, et al, Phys. Lett. A 326: 187-198 (2004)]. The result again affirms our observation that different systems, having the same matrix representation, have similar properties.