Cannot set 'type' and 'format' for an <hot-colum> binding them to variable/function

[dfiori]

I cannot set the type and format for an <hot-column ...> element using a binding with controller variable or function. I'm using my own Column object and I set params this way:
<hot-column .. ng-repeat="oCol in $ctrl.getColumns()" type="'{{oCol.getType()}}'" format="'{{oCol.getFormat()}}'">