I think you get ajax elements no different from any other elements. The problem (I've run into at least) is that there is no definitive way to know when those ajax elements have finished loading. In our application I've had the dev team create a div called "ajaxFinished" and I look for it to let me know when the ajax piece is finished. To see the autocomplete items in google, I think this will work (not sure if that was your question, but...)
<font class="small">Code:</font><hr /><pre>
this = Browser("B").Page("P").WebElement("class:=gstl_0 gssb_c").GetROProperty("column names")
this = split(this, "I'm Feeling Lucky »")
For x = 0 to ubound(this)
A good rule of thumb is to never measure with your thumb.