TaskProcessing adding custom filter

Hi Experts,

We are facing a requeriment in myinbox and we dont know if it is possible.

We need to add a new filter (to the filters popup , in the bottom of the page) using a custom property.

¿Is it possible? We know we can add new filters extending de myInbox app, (implementing the extHookChangeFilterItems and extHookChangeFilterItems methods in s2.controller) and we know we can extend the TaskProcessing service to add new attributes to the workitems returned by the TaskCollection entity Set.

But the "filter" parameter in the odata call does not work with those custom attributes added to the taskCollection.

¿Is there anything else we need to do?

Thanks in advance for your help