Get custom filtering active filters

I'm using the following method to add custom filtering features:
$.fn.dataTable.ext.search.push(function(oSettings, aData) {});

How can I obtain back which filter value is active on each column?

Also, if I save the table state with stateSaveCallback, those filters won't be saved. This makes me think that applying custom filters this way it's completely different from use this method: table.columns(colId).search(searchString, true, false).draw(true)
But how to use the custom one as if it is the standard one?