jQuery datepicker mindate, maxdate

I have the two following datepicker objects but I can't get what I want as I am getting stuck with the minDate and maxDate options:

This is to restrict the dates to future dates.

What I want: restrict the dates from current date to 30 years time.

What I get: restrict the dates from current date to 10 years time.

$(".datepickerFuture").datepicker({
    showOn: "button",
    buttonImage: 'calendar.gif',
    buttonText: 'Click to select a date',
    duration:"fast",
    changeMonth: true,
    changeYear: true,
    dateFormat: 'dd/mm/yy',
    constrainInput: true,
    minDate: 0,
    maxDate: '+30Y',    
        buttonImageOnly: true
    });

This is to restrict to select only past dates:

What I want: restrict the dates from current date to 120 years ago time.

What I get: restrict the dates from current date to 120 years ago time, but when I select a year the maximum year will reset to selected year (e.g. what I would get when page load from fresh is 1890-2010, but if I select 2000 the year select box reset to 1880-2000) .

$(".datepickerPast").datepicker({
    showOn: "button",
   buttonImage: 'calendar.gif',
    buttonText: 'Click to select a date',
    duration:"fast",
    changeMonth: true,
    changeYear: true,
    dateFormat: 'dd/mm/yy',
    constrainInput: true,
    yearRange: '-120:0',
    maxDate: 0,
    buttonImageOnly: true
});

I need help with both datepicker object, any help would be very much appreciated.

I fixed my problem which it was the jquery libraries were a bit out date.

If anyone interested on this solution please check here.