Question
What is the most sucessful way to get peony seeds to sprout and what is the best way to divide an Itoh peony?

Answer
Hi Inette,
Thanx for your question.  I'm sorry about the delay.  I just got back from vacation and forgot to change my profile to indicate such.  I apologize for any inconvenience this may have caused.

I recently posted an answer to a similar question.  You can use the search function above and often find many of these questions already answered if you want to save yourself a little time.  At any rate, here is your answer.

1.  Harvest seed as soon as it is ripe.
2.  Plant in situ (in a spot out in the garden that you can protect from weeds and varmints) or plant in a pot of good potting soil and plant the black or dark brown seeds down about 1.5 inches deep.  Cover and keep moist.  They will not germinate until they have gone through a cold winter and sometimes it will take a year or more to germinate.  The thing is, they need a long period of cold temperatures.  The tree peony does not grow in zones warmer than zone 8.  You can also put the seed in a damp paper towel and place it inside of a plastic baggie and leave it in the refrigerator for 4-6 months.  Remove the seed and plant as described above.  
3.  When the seed germinates, it will only grow roots the first year and then go through the winter in a dormant state.  The next spring, new leaves will emerge from the soil.  Allow the seedling to grow where it is until it is a manageable size and then you can gently prick it out of the soil and plant in a separate pot.  
4.  It will take 4 or 5 years to produce a bloom after the seed has germinated so it could take a total of 6 or 7 years.  It's not something for someone who wants something quick but I can see the interest in growing these from seed.

As far as dividing the Itoh peony?  Here is what the American Peony Society (APS) says.

http://www.americanpeonysociety.org/index.php?moduleId=cgkcUjNV&articleId=FxmX7w...

I hope this helps.
Tom