Role of the entry capillary pressure (Pce)-- Modification the model Van Genuchten.

Dear all,
I'm a new member. I started to simulate the migration of hydrogen using the EOS 5 -TOUGH 2. Like the topic title, I would like to find out about the role of the entry capillary pressure.

The capillary pressure curve  that I used corresponded to the VG (Van Genuchten) model. In order to approach the BC model, I wish to modify the model VG. However, I do still not know how to do in the EOS 5 (TOUGH 2) (modification Sls?) and how to get additional printout so I can figure out what is going on.

Is there anyone who has some experience with it ? Please give some suggestions. I'm looking forward to getting your reply.

With kind regards,

Trung