linux idsn active-filter trouble

hi all
i'm having trouble setting active-filter in ioptions file
and nothing but default config works. is there anyone that can help we this
issue becouse i'm going slightly mad :-)))
yes, kernel 2.6, pppd 2.4.3, ipppd 2.1.2 and i want tu DOD for just some
traffic and not for all like defautl ioptions file does.
thanks
branimir


Brane