How to read Editor Presentation properties from DOJO?

Workitem Editors can be parameterized with a set of default key/value pairs such as labelVisible, hideIfEmpty etc. How can these values be read from the dojo script that is deployed with the custom editor presentation?

If you check how this represented in the process source it is very simple and very generic:

<presentation attributeId="someid" description="somedesc" kind="com.ibm.team.workitem.kind.contributor"> 
   <property key="labelVisible" value="true"/> 
</presentation> 

I have written a custom workitem editor and that works just fine. Now I want to parameterize this with my own key/value pairs, like so:

<presentation attributeId="someotherid" description="somedesc" kind="my.own.wi.editor"> 
   <property key="labelVisible" value="true"/>  
   <property key="myprop" value="hello world!"/> 
</presentation> 

How can I read the built-in props from DOJO and would I be able to use that for arbitrary (non-boolean) values of my own design like shown above?

Any help would be greatly appreciated!

Thanks, Nils