[jQuery] Validate

Hi
I like the validate plugin, but it only works with values defined on
load, not dynamic values. I'd like to be able to compare field values.
For example, if I got 2 fields: #start_value and #end_value and I want
to check the end_value is bigger than start_value, should be something
like this:
$("#myform").validate({
rules: {
end_value: {
required: true,
min: '#start_value'
}
}
});