currentdate + 2 for datepicker

currentdate + 2 for datepicker

hi 
for a datepicker
but i have some questions
i made it already posible 
- to have an inline input field with the calender
- disabled the sundays
- start at currentdate
but i want the following. people dont go back in time (done), and the startdate has to be 2 days more than the currentdate and sundays not counted.
by example; today 8/5 must the startdate be 11/5 (because sundays are not included). another example; on 10/5 has to start by 12/5. 
what to do? i already tried something with startedate and mindate, but was not working by me.
hope someone can help me
greetz henk NL