Impossible to change the value of "Name of the service validate servlet" from the interface

Hello and thanks for your work on this great plugin,

I am trying to make it work with a CAS engine (not JASIG), but I am running into trouble.
By default, wp-cassify uses "p3/serviceValidate" as "Name of the service validate servlet", event though, the label says it should be "serviceValidate" by default:

When I try to change it via the Wordpress Admin UI, it always reverts to "p3/serviceValidate", so I need to do it via the mysql database directly. It looks like there are two issues:
- The label should say "Name of the service validate servlet (Default : p3/serviceValidate)
- The value should be editable

Thanks!
Fabien