How can I set datetime picker minDate dynamically?

I'm using a datetimepicker by trentrichardson.com. I have a form with two input fields: "from" and "to" and want to be able to dynamically set a minDate to my "to" field equal to the value of my "from" field.

I know I should use a beforShow option but don't know how to implement the function.

$('.from,.to').datetimepicker({

    beforeShow: customRange

});