I have the two following datepicker objects:
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.
Thanks in advance.
Cesar.