It will be possible to create a non-linear RadSlider, the items/values of which will not be positioned evenly on the slider track. This distribution of the items/values will be determined by a custom function.
When ItemType=Item and AutoPostBack=true RadSlider performs the postback in the onmousedown event of the increase/decrease handles. This should happen only when the button is clicked with this item type, because there isn't a small change. This will allow the end user to change his/her mind like a regular button would allow you to click, hold the mouse button down, move the mouse out of the button and release without performing the postback.