Newbie question

Hi
Sorry my perhaps trivial question.
I have searched the net a lot and cant resolve my issue.
I use Openbsd 4.1 and the default wm fvwm.
I want to do these things
1-To start a program (namely rdesktop with some parameters) when a
user logins to x.
2-Alternatively, add a menu item to fvwm menu which launches rdesktop program.
I have tried locating some .fvwm2rc/config  files in different places
but they seemed
to affect nothing.
Could you help me?
For being simple and ligth i dont want to install  any X related
program(namely other
wms or other gui programs).