Select the Arpeggiator in the Environment and you'll see all the options in the Inspector (left side).
There are plenty more ways to make your own menus and buttons / sliders to control these settings - but it's far too lengthy to explain here - better to check out the Logic TNT series of video tutorials :)
Hope that helps
P.S. Do please reply to the original thread/post - it makes it easier for us and others to follow the conversation. Cheers. :)