Hello, I believe that the Delete button removes the item from a copy of the values returned by getValue() method and stored in memory. You need to write the copy back to the document like this:
var tmpValues:java.util.Vector = document1.getValue("CarQualMin");
tmpValues.remove(itemIndex);
document1.replaceItemValue("CarQualMin", tmpValues);
Did you consider using the Dojo List Text Box component from the Upgrade Pack 1? It renders multivalue field items with a small x next to each item allowing you to easily delete that particular value, very handy. You can than have an edit box bound to, for example, a request scope variable and a button which adds value from that variable to the document item. Something like this works for me:
<xp:inputText value="#{requestScope.newCarMin}" styleClass="fld" id="inputText3"></xp:inputText>
<xp:button value="Add" id="button1">
<xp:eventHandler event="onclick" submit="true"
refreshMode="complete">
<xp:this.action><![CDATA[#{javascript:var tmpValues = document1.getItemValue("CarQualMin"); //read current values
tmpValues.add(requestScope.get("newCarMin")); //add a new one bound to edit field
document1.replaceItemValue("CarQualMin", tmpValues); //store the values back to document
requestScope.put("newCarMin", ""); //and clear the scope variable to clear the edit field}]]></xp:this.action>
</xp:eventHandler></xp:button>