[TYPO3-mvc] Error with array argument in Ajax action.

[Dirk Wenzel]

Hi,
I got a Controller with an ajax action.
When calling the action with an (json) array as argument it fails with 
this message:

#1297759968: Exception while property mapping at property path "":No 
converter found which can be used to convert from "array" to "array".

The wiki page which is linked in the error page does not tell anything 
about this kind of error.

I guess I should tell the PropertyMapper to use the TypeConverter 
ArrayConverter. But I can't figur out howl

Here is my code:
JavaScript:
var overwriteDemand = 
{"positionTypes":"","sectors":"2","categories":"","categoryConjunction":"or","clientsPositionsOnly":"1"};

$.ajax({
   async: 'true',
   url: 'index.php',
   type: 'POST',
   data: {
     eID: "placementsAjax",
     request: {
       pluginName: 'Placements',
       controller: 'Position',
       action: 'ajaxList',
       arguments: {
        'overwriteDemand': overwriteDemand,
       }
     }
   },[...]
As you can see, the request is routed by an Ajax Dispatcher.

Controller:
/**
  * action ajaxList
  *
  * @param \array $overwriteDemand
  * @return void
  */
public function ajaxListAction($overwriteDemand = NULL) {[...]}

Thanks in advance
Dirk