I attached the plugin to Feflow of considering hydraulic head as parameter (Edit the written one posted by adacovsk) and I tested it. FeFlow is working changing the boundary conditions by the values written in .fpi file. After building FePEST model, defining IFM implemented with the same names and running it. The contribution of regul_xxpgp to phi is zero and nothing changed regarding those BC parameters.
Can anyone help me to know how to define IFM-plugin correctly and make it working with FePEST?.