Well found. Sorry, that got past my testing.
I found the problem. In the com.ibm.cadmo.core project, com.ibm.cademo.core.ComponentViewPart class, line 449. It is:
String val = element.getAttribute("key");<br/>
and should be
String val = element.getAttribute(key);<br/>
That fault will cause all properties and actions with non-string types to come out as strings. I've made the fix but I need to run a full regression before I post it (because it is in core). If you are using 8.0.2 you can turn off strict type checking when wiring and it will still let you wire it. Or, of you are playing with the source, you can make the above change yourself.
Thanks for spotting this!
Jo