The databases give conflicting advice---probably they were dealing with different varieties. They definitely require chilling so winter sow sounds right.
see tomclothier.hort

May need two winters to break dormancy for Dictamus alba if sown now. It's a difficult one to germinate and apparently needs 5 months cold treatment before warm temperatures to stimulate root growth for good percentage of germination. And I also read that two year old seed germinates better at warm temperatures, go figure. I am assuming no cold treatment before hand but not sure. You might want to save the seed for another year and try warm temps first (over summer). If no germination, leave pots outside all winter for germination in the summer of 2012. :)
If I remember correctly, I sowed a pot of Dictamus alba seeds in November of 2008. Finally saw several sprouts in August of 2009. I've left them to grow stronger roots in their pots for another year and also for the remaining seeds to germiante.

Thanks My info has led me to think I'll do a wintersow now>I'm going to put 2-3 seeds in each pot and put them in the warm garage for a few days after I water them . I'm going to put them outside at the new property in a protected site( where HB won't be using machinery), cover with snow and let them go. In 2 years when I'll be ready for them Hopefully they will be ready for me.
Lois

I've had many seedlings pop up around the parent plants, but I do suspect that the seed has sat there for 2 years. I've tried winter sowing them through one season, and nothing ever sprouted.

Good luck!