Passing octave function as a parameter

[Eduardo Gallestey]

Hi,

I trying to adapt a C++/Fortran subroutine (related to the solution of
PDE) for use in the "octave environment". I am so far that I can pass
numerical parameters to it and get correct calculations. 

Now I would like have "octave functions" as parameters. This is
possible, because it has been done (at least!) for the routines "lsode"
and "fsolve"!. 
Is there some documentation with respect to that? Can someone explain
how this should be done?

I would appreciate any help.

Eduardo