The manual section "18.104.22.168. config-type field" gives an example of list:
lists, sets and collections. In that case each element of the xml-content is consitered as an element of the collection and is parsed, recursively applying the conversions. If the type of the elements is different from java.lang.String this can be indicated by specifying a type attribute with the fully qualified type name. For example, following snippet will inject an ArrayList of Strings into field 'numbers'<numbers> <element>one</element> <element>two</element> <element>three</element> </numbers>
The text in the elements can be converted to any object that has a String constructor. To use another type then String, specify the element-type in the field element ('numbers' in this case).
I'd have to look up other examples from the testcases in the source. Currently have no time to do that since I'm off preparing for the jBPM Community Day
You can ofcourse do that yourself (and when you are at it, update/upgrade the docs ;-))