fortran subroutine for physical properties in Aspen

[pippozzo]

I'm trying to simulate with Aspen Plus, a process of fractionation of a mixture of some components that aren't in Aspen data bank. I used the unit operation of "flash" to simulate a teorical stage of extraction column. I've got an experimental relationship between the liquid/vapor equilibrium coefficients (Ki=yi/xi) and the composition of the mixture. I tryed to use the fortran subroutine kvlu.f but this subroutine gives results only if the components used are in the Aspen data bank: Aspen uses the user K-values as fugacity coefficients for the liquid phase and it calculates the vapor pressures of the components with Antoine's law. So if you haven't got the Antoine coefficients Aspen doesn't finish its simulation. What do you think about my problem? Am I using a wrong unit operation? How can I supply my K-values to Aspen?
Best reguards X-)